in conclusion , we report a ketyl  olefin 
 coupling for the 
 preparation of substituted 3-benzylchroman-4-ols , promoted by visible 
 light photoredox catalysis .
importantly , we uncovered trialkylamines 
 as a cheap and readily available alternative to the previously reported 
 electron  proton donor system consisting of hantzsch ester / brnsted 
 acid . by employing the trialkylamine / photocatalyst system , we have 
 been able to develop an efficient intramolecular ketyl 
the formal hydroacylation protocol provides the chromanol derivatives 
 in good yield under mild reaction conditions and with low catalyst 
 loadings .
all reactions were performed with 
 oven - dried glassware and under an inert atmosphere ( argon ) unless 
 otherwise stated .
acetonitrile was distilled from calcium hydride 
 and stored over 4  molecular sieves under nitrogen / argon atmosphere . 

chromatographic 
 purification of products was carried out using silica gel ( 230400 
 mesh ) .
thin - layer chromatography was carried out using aluminum plates 
 coated with silica ( 230400 mesh ) which were visualized under 
 uv light ( 254 nm ) or by staining with aqueous potassium permanganate 
 solutions or vanillin alcoholic solution .
h nmr spectra 
 were recorded in deuterated solvents on spectrometers at 300 , 400 , 
 or 600 mhz with residual protic solvent as the internal standard .
c nmr spectra were recorded in deuterated solvents on spectrometers 
 at 75 , 101 , or 151 mhz with the central peak of the deuterated solvent 
 as the internal standard .
chemical shifts (  ) are given in parts 
 per million ( ppm ) , and coupling constants ( j ) are 
 given in hertz ( hz ) rounded to the nearest 0.1 hz . the h nmr spectra are reported as  downfield from tetramethylsilane 
 ( multiplicity , coupling constant j , number of protons ) . 

the c nmr spectra are reported as . for the f - containing 
 compound ( 2c ) , a simultaneously proton and fluorine decoupled c nmr spectrum was recorded .
assignments are aided by the 
 use of dept-135 , cosy and hmqc spectra where necessary .
low resolution mass spectra 
 ( ei / ci ) were recorded on a mass spectrometer with ( ei ) or ( ci ) detectors . 

high - resolution mass spectrometry ( hrms ) was performed by ei using 
 a double - focusing mass spectrometer and by esi using a hybrid ion - trap 
 mass spectrometer .
a 
 schlenk tube was charged with aldehyde 1 ( 1 equiv ) , catalyst 
 pc 3 ( 1 or 2.5 mol % ) , and degassed dipea ( 2.5 equiv ) . 

the vial was placed 
 in a 100 ml beaker containing a blue led strip glued on the inner 
 wall , and the reaction mixture was stirred for 15 h. after this time , 
 the solvent was evaporated , and the reaction mixture was purified 
 on silica gel ( gradient pentane / etoac 95:5 ) .
the title compound 
 was synthesized according to the general 
 procedure employing 1a ( 0.12 mmol , 28.6 mg ) , 1 mol % 
 ( 1.1 mg ) of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the 
 product was purified by flash column chromatography : yield 80% ( 23 
 mg ) ; anti / syn 1:1 ; h 
 nmr ( 600 mhz , cdcl3 )  7.347.18 ( m , 14h ) , 
 6.96 ( td , j = 7.5 , 0.9 hz , 1h ) , 6.90 ( dd , j = 10.6 , 4.2 hz , 2h ) , 6.85 ( d , j = 8.5 
 hz , 1h ) , 4.51 ( dd , j = 9.4 , 3.1 hz , 2h ) , 4.23 ( dd , j = 11.1 , 2.6 hz , 1h ) , 4.144.05 ( m , 2h ) , 3.98 ( dd , j = 11.1 , 4.2 hz , 1h ) , 2.89 ( dd , j = 13.8 , 
 8.4 hz , 1h ) , 2.752.64 ( m , 2h ) , 2.54 ( dd , j = 13.8 , 9.3 hz , 1h ) , 2.402.29 ( m , 1h ) , 2.282.17 
 ( m , 1h ) , 1.92 ( bs , 1h ) , 1.74 ( bs , 1h ) ; c nmr ( 151 mhz , 
 cdcl3 )  154.3 , 154.2 , 139.2 , 139.1 , 130.2 , 130.1 , 
 129.9 , 129.8 , 129.1 ( 2c ) , 128.6 , 128.5 , 126.3 ( 2c ) , 124.1 , 123.2 , 
 120.9 , 120.5 , 116.9 ( 2c ) , 67.6 , 64.9 ( 2c ) , 64.6 , 41.5 , 40.0 , 34.6 , 
 32.8 ; ft - ir max(atr ) cm 3372 , 
 2922 , 1582 , 1485 , 1450 , 1302 , 1264 , 1222 , 1119 , 1074 , 1039 , 909 , 748 , 
 698 ; m / z ( ei ) 240 ( [ m ] , 100 ) , 91 ( [ phch2 ] , 28 ) ; hrms ( esi ) calcd 
 for [ c16h16o2 + na ] 263.10425 , 
 found 263.10419 .
the 
 title compound was synthesized according to the general procedure 
 employing 1b ( 0.12 mmol , 38.1 mg ) , 2.5 mol % ( 2.74 mg ) 
 of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product 
 was purified by flash column chromatography : yield 50% ( 19.1 mg ) ; anti / syn 1.1:1 ; h nmr ( 400 
 mhz , cd3od )  7.45 ( d , j = 2.4 hz , 
 1h , syn ) , 7.34 ( d , j = 3.1 hz , 1.1 
  1h , anti ) , 7.317.13 ( m , 12.6h ) , 6.736.65 
 ( m , 2.1h ) , 4.47 ( d , j = 3.4 hz , 1h , syn ) , 4.36 ( d , j = 5.0 hz , 1.1  1h , anti ) , 4.13 ( dd , j = 11.2 , 2.8 hz , 1.1  1h , anti ) , 4.033.94 ( m , 2h , syn ) , 3.89 
 ( dd , j = 11.1 , 5.5 hz , 1.1  1h , anti ) , 2.87 ( dd , j = 13.6 , 7.1 hz , 1h , syn ) , 2.76 ( dd , j = 13.8 , 6.1 hz , 1h , syn ) , 2.55 ( dd , j = 13.6 , 8.3 hz , 1.1  1h , anti ) , 2.45 ( dd , j = 13.7 , 9.3 hz , 1.1 
  1h , anti ) , 2.252.17 ( m , 1h , syn ) , 2.162.08 ( m , 1.1  1h , anti ) ; c nmr ( 101 mhz , cd3od )  153.5 ( 2c ) , 
 139.4 , 139.2 , 132.4 ( 2c ) , 131.60 ( 2c ) , 128.8 , 128.7 , 128.1 ( 2c ) , 127.0 , 
 126.1 , 126.0 , 125.8 , 118.1 ( 2c ) , 111.9 , 111.5 , 66.4 , 65.0 , 64.8 , 64.2 , 
 41.5 , 40.2 , 34.2 , 32.1 ; ft - ir max(atr ) cm 2926 , 1479 , 1407 , 1260 , 1224 , 1191 , 1085 , 1055 , 1021 , 819 , 748 , 
 699 ; m / z ( ei ) 319 ( [ m ] , 9 ) , 91 ( [ phch2 ] , 100 ) ; hrms ( ei ) calcd for 
 [ c16h15o2br ] 318.02499 , found 318.02492 .
the 
 title compound was synthesized according to the general procedure 
 employing 1c ( 0.12 mmol , 30.8 mg ) , 1 mol % ( 1.1 mg ) of 
 pc 3 and 2.5 equiv of dipea ( 38.8 mg ) .
the product was 
 purified by flash column chromatography : yield 43% ( 13.2 mg ) ; mp = 102104 
 c ; anti / syn 1.1:1 ; h nmr ( 600 mhz , cd3od )  7.317.23 ( m , 6.5 
 h ) , 7.217.15 ( m , 4.3 h ) , 7.06 ( dd , j = 9.0 , 
 3.1 hz , 1.1  1h , anti ) , 6.96 ( dd , j = 8.9 , 3.1 hz , 1h , syn ) , 6.89 ( dtd , j = 11.6 , 8.5 , 3.1 hz , 2h ) , 6.786.71 ( m , 2h ) , 4.48 ( d , j = 3.5 hz , 1h , syn ) , 4.37 ( d , j = 5.1 hz , 1.1  1h , anti ) , 4.12 
 ( dd , j = 11.1 , 2.8 hz , 1.1  1h , anti ) , 4.013.94 ( m , 2h , syn ) , 3.87 ( dd , j = 11.1 , 5.6 hz , 1.1  1h , anti ) , 
 2.88 ( dd , j = 13.6 , 7.2 hz , 1h , syn ) , 2.79 ( dd , j = 13.8 , 6.0 hz , 1.1  1h , anti ) , 2.56 ( dd , j = 13.6 , 8.3 hz , 1h , syn ) , 2.46 ( dd , j = 13.8 , 9.4 hz , 1.1  
 1h , anti ) , 2.242.17 ( m , 1h , syn ) , 2.162.11
( m , 1.1  1h , anti ) ; f nmr ( 564 mhz , cd3od )  125.8 , 
 126.4 ; c nmr ( 101 mhz , cd3od )  
 156.9 , 156.6 , 150.4 , 150.3 , 139.5 , 139.2 , 128.8 , 128.7 , 128.1 , 128.0 , 
 125.9 ( 2c ) , 125.8 , 125.0 , 117.2 , 117.1 , 115.5 , 115.4 , 115.3 ( 2c ) , 
 66.8 , 65.0 , 64.7 , 64.4 , 41.6 , 40.3 , 34.2 , 32.1 ; ft - ir max(atr ) cm 3370 , 2926 , 2493 , 1488 , 1436 , 
 1251 , 1201 , 1027 , 736 , 698 ; m / z ( ei ) 
 258 ( [ m ] , 48 ) , 91 ( [ phch2 ] , 100 ) ; 
 hrms ( ei ) calcd for [ c16h15o2f ] 258.10506 , found 258.10537 . the title compound was synthesized according 
 to the general 
 procedure employing 1d ( 0.12 mmol , 35.6 mg ) , 1 mol % 
 ( 1.1 mg ) of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the 
 product was purified by flash column chromatography : yield 51% ( 18.2 
 mg ) ; anti / syn 1.3:1 ; h nmr ( 400 mhz , cd3od )  8.05 ( d , j = 2.1 hz , 1.3  1h , anti ) , 7.92 ( d , j = 2.2 hz , 1h , syn ) , 7.80 ( ddd , j = 14.4 , 8.6 , 2.2 hz , 2.3h ) , 7.327.11 ( m , 11.5h ) , 
 6.81 ( dd , j = 14.4 , 8.6 hz , 2.3h ) , 4.52 ( d , j = 3.2 hz , 1h , syn ) , 4.42 ( d , j = 4.9 hz , 1.3  1h , anti ) , 4.21 
 ( dd , j = 11.2 , 2.9 hz , 1.3  1h , anti ) , 4.113.99 ( m , 2h , syn ) , 3.96 ( dd , j = 11.1 , 5.3 hz , 1.3  1h , anti ) , 
 3.84 ( s , 1.3  3h , anti ) , 3.81 ( s , 3h , syn ) , 2.88 ( dd , j = 13.6 , 7.1 hz , 1h , syn ) , 2.75 ( dd , j = 13.7 , 6.1 hz , 1.3  
 1h , anti ) , 2.56 ( dd , j = 13.6 , 8.3 
 hz , 1h , syn ) , 2.43 ( dd , j = 13.7 , 
 9.3 hz , 1.3  1h , anti ) , 2.262.13 ( m , 
 2.3h ) ; c
nmr ( 101 mhz , cd3od )  167.0 
 ( 2c ) , 158.6 ( 2c ) , 139.4 , 139.1 , 132.3 , 132.2 , 130.4 , 130.3 , 128.8 , 
 128.7 , 128.1 ( 2c ) , 126.0 , 125.9 , 124.8 , 123.9 , 122.1 , 121.7 , 116.3 
 ( 2c ) , 66.4 , 65.4 , 65.2 , 64.2 , 51.0 , 50.9 , 41.4 , 40.2 , 34.2 , 32.2 ; 
 ft - ir max(atr ) cm 2949 , 1711 , 
 1611 , 1496 , 1436 , 1253 , 1192 , 1125 , 1012 , 767 , 700 ; m / z ( ei ) 298 ( [ m ] , 12 ) , 91 ( [ phch2 ] , 40 ) ; hrms ( ei ) calcd for [ c18h18o4 ] 298.11996 , found 298.12009 .
the title compound was synthesized according 
 to the general procedure employing 1e ( 0.12 mmol , 42.4 
 mg ) , 1 mol % ( 1.1 mg ) of pc 3 , and 2.5 equiv of dipea 
 ( 38.8 mg ) .
the product was purified by flash column chromatography : 
 yield 44% ( 18.7 mg ) ; anti / syn 1.6:1 ; h nmr ( 600 mhz , cdcl3 )  7.497.15 
 ( m , 15.6h ) , 7.08 ( dd , j = 8.8 , 2.6 hz , 1.6  
 1h , anti ) , 6.99 ( dd , j = 8.8 , 2.6 
 hz , 1h , syn ) , 6.80 ( d , j = 8.8 hz , 
 1.6  1h , anti ) , 6.76 ( d , j = 8.8 hz , 1h , syn ) , 6.456.24 ( m , 2.6h ) , 
 4.524.41 ( m , 2.6h ) , 4.19 ( dd , j = 11.0 , 1.9 
 hz , 1.6  1h , anti ) , 4.124.01 ( m , 2h , syn ) , 3.92 ( dd , j = 11.0 , 3.9 hz , 1.6  
 1h , anti ) , 2.86 ( dd , j = 13.5 , 8.6 
 hz , 1h , syn ) , 2.732.61 ( m , 2.6h ) , 2.51 ( dd , j = 13.7 , 9.5 hz , 1.6  1h , anti ) , 
 2.312.26 ( m , 1h , syn ) , 2.212.17 ( m , 
 1.6  1h , anti ) , 1.911.62 ( overlapping 
 of two bs , 2.6h ) 1.51 ( s , 1.6  9h , anti ) , 1.48 
 ( s , 9h , syn ) ; c nmr ( 151 mhz , cdcl3 )  153.2 , 153.1 , 150.3 , 150.2 , 139.2 , 139.1 , 131.4 , 
 131.3 , 131.0 ( 2c ) , 129.1 ( 2c ) , 128.5 ( 2c ) , 126.3 ( 2c ) , 124.4 , 123.5 , 
 121.2 , 120.7 , 117.2 , 117.1 , 80.4 ( 2c ) , 67.6 , 65.1 , 64.8 , 64.6 , 41.3 , 
 40.0 , 34.6 , 32.7 , 28.4 , 28.3 ; ft - ir max(atr ) cm : 3350 , 2981 , 2932 , 1696 , 1499 , 1454 , 1367 , 1309 , 
 1241 , 1218 , 1163 , 1023 , 822 , 733 , 699 ; m / z ( ei ) 298 ( [ m  ( ch3)3c ] , 100 ) , 91 ( [ phch2 ] , 67 ) ; hrms ( ei ) 
 calcd for [ c16h16o2n1 ] ( [ m  boc ] ) 254.11756 , found 254.11706 .
the 
 title compound was synthesized according to the general procedure 
 employing 1f ( 0.12 mmol , 37.7 mg ) , 1 mol % ( 1.1 mg ) of 
 pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product was 
 purified by flash column chromatography : yield 61% ( 23 mg ) ; anti / syn 1.2:1 ; h nmr ( 600 
 mhz , cd3od ) 7.487.44 ( m , 1.2  1h , anti ) , 7.447.40 ( m , 1h , syn ) , 7.377.05 
 ( m , 24.2h ) , 7.006.94 ( m , 1.2  1h , anti ) , 6.926.86 ( m , 1h , syn ) , 4.49 ( d , j = 2.7 hz , 1h , syn ) , 4.44 ( d , j = 4.1 hz , 1.2  1h , anti ) , 4.15 
 ( dd , j = 11.0 , 2.6 hz , 1.2  1h , anti ) , 4.00 ( t , j = 10.9 hz , 1h , syn ) , 3.92 ( dd , j = 10.6 , 3.5 hz , 1h , syn ) , 3.86 ( dd , j = 11.0 , 4.5 hz , 1.2  1h , anti ) , 2.85 ( dd , j = 13.5 , 7.5 hz , 1h , syn ) , 2.70 ( dd , j = 13.7 , 6.4 hz , 1.2  
 1h , anti ) , 2.55 ( dt , j = 18.0 , 9.0 
 hz , 1h , syn ) , 2.512.44 ( m , 1.2  1h , anti ) , 2.252.18 ( m , 1h , syn ) , 2.172.12 
 ( m , 1.2  1h , anti ) ; c nmr ( 151 
 mhz , cd3od )  151.1 ( 2c ) , 139.6 , 139.4 , 138.5 , 138.4 , 
 130.2 , 130.1 , 129.8 ( 2c ) , 129.7 ( 2c ) , 129.2 ( 2c ) , 128.8 , 128.7 , 128.1 
 ( 2c ) , 127.5 ( 2c ) , 126.4 ( 2c ) , 125.9 , 125.8 , 125.1 , 123.9 , 120.2 , 119.9 , 
 67.1 , 64.8 , 64.6 , 64.5 , 41.5 , 40.3 , 34.3 , 32.5 ; ft - ir max(atr ) cm 1594 , 1496 , 1469 , 1430 , 1219 , 
 1017 , 754 , 697 ; m / z ( ei ) 316 ( [ m ] , 63% ) , 91 ( [ phch2 ] , 27% ) ; hrms ( esi ) 
 calcd for [ c22h20o2 + na ] 339.13555 , found 339.13525 . the 
 title compound was synthesized according to the general procedure 
 employing 1 g ( 0.12 mmol , 30.3 mg ) , 1 mol % ( 1.1 mg ) of 
 pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product was 
 purified by flash column chromatography : yield 56% ( 17.1 mg ) ; anti / syn 1.4:1 ; h nmr ( 600 
 mhz , cd3od )  7.307.21 ( m , 7.5h ) , 7.207.12 
 ( m , 5.5h ) , 7.057.02 ( m , 2.4h ) , 6.99 ( d , j = 7.3 hz , 1.4  1h , anti ) , 6.80 ( t , j = 7.5 hz , 1h , syn ) , 6.73 ( t , j = 7.5 hz , 1.4  1h , anti ) , 4.45 
 ( d , j = 3.2 hz , 1.4  1h , anti ) , 4.38 ( d , j = 4.2 hz , 1h , syn ) , 4.19 ( dd , j = 11.0 , 2.6 hz , 1h , syn ) , 4.064.02 ( m , 1.4  2h , anti ) , 3.94 
 ( dd , j = 11.0 , 4.6 hz , 1h , syn ) , 
 2.87 ( dd , j = 13.7 , 7.4 hz , 1.4  1h , anti ) , 2.68 ( dd , j = 13.7 , 6.5 hz , 1h , syn ) , 2.58 ( dd , j = 13.6 , 8.1 hz , 1.4  
 1h , anti ) , 2.45 ( dd , j = 13.7 , 9.1 
 hz , 1h , syn ) , 2.16 ( s , 3h , syn ) , 
 2.12 ( s , 1.4  3h , anti ) oh signals not observed ; c nmr ( 151 mhz , cd3od )  152.3 , 152.2 , 139.7 , 
 139.5 , 129.9 , 129.8 , 128.8 , 128.7 , 128.1 ( 2c ) , 127.9 , 127.8 , 125.8 
 ( 2c ) , 125.2 ( 2c ) , 123.9 , 122.7 , 119.6 , 119.3 , 66.9 , 64.7 , 64.6 , 64.4 , 
 41.8 , 40.6 , 34.3 , 32.6 , 14.8 ( 2c ) ; ft - ir max(atr ) 
 cm 3352 , 2919 , 1598 , 1472 , 1258 , 1210 , 1092 , 1023 , 
 747 , 698 ; m / z ( ei ) 254 ( [ m ] , 59 ) , 253 ( [ m  1 ] , 100 ) , 91 ( [ phch2 ] , 39 ) ; hrms ( ei ) calcd for [ c17h18o2 ] 254.13013 , found 254.13046 .
the title 
 compound was synthesized according 
 to the general procedure employing 1h ( 0.12 mmol , 42.1 
 mg ) , 1 mol % ( 1.1 mg ) of pc 3 , and 2.5 equiv of dipea 
 ( 38.8 mg ) .
the product was purified by flash column chromatography : 
 yield 88% ( 37.5 mg ) ; anti / syn 1.2:1 ; h nmr ( 400 mhz , cd3od )  7.337.07 
 ( m , 15.4h ) , 4.48 ( d , j = 3.5 hz , 1h , syn ) , 4.39 ( d , j = 3.3 hz , 1.2  1h , anti ) , 4.13 ( dd , j = 10.9 , 2.5 hz , 1.2  1h , anti ) , 4.033.94 ( m , 2h , syn ) , 3.90 
 ( ddd , j = 10.9 , 4.0 , 1.1 hz , 1.2  1h , anti ) , 2.88 ( dd , j = 13.5 , 7.2 hz , 1h , syn ) , 2.67 ( dd , j = 13.6 , 6.0 hz , 1.2  
 1h , anti ) , 2.57 ( dd , j = 13.5 , 8.3 
 hz , 1h , syn ) , 2.42 ( dd , j = 13.6 , 
 9.8 hz , 1.2  1h , anti ) , 2.232.15 ( m , 
 1h , syn ) , 2.142.08 ( m , 1.2  1h , anti ) , 1.37 ( s , 1.2  9h , anti ) , 1.33 
 ( s , 9h , syn ) , 1.29 ( s , 1.2  9h , anti ) , 1.25 ( s , 9h , syn ) ; c nmr ( 101 mhz , 
 cd3od )  150.6 ( 2c ) , 141.8 , 141.5 , 139.8 , 139.6 , 
 136.3 , 136.1 , 128.8 ( 2c ) , 128.0 ( 2c ) , 125.8 , 125.7 , 125.2 , 124.7 , 
 124.0 , 123.1 , 123.0 , 122.4 , 67.7 , 65.5 , 63.9 , 63.0 , 41.7 , 40.6 , 34.5 , 
 34.5 , 34.3 , 33.7 , 33.7 , 32.5 , 30.7 ( 2c ) , 28.9 ( 2c ) ; ft - ir max(atr ) cm 2956 , 2870 , 1479 , 1450 , 1361 , 
 1229 , 1171 , 1130 , 1028 , 882 , 749 , 701 , 532 ; m / z ( ei ) 352 ( [ m ] , 65 ) , 91 ( [ phch2 ] , 15 ) ; hrms ( ei ) calcd for [ c24h32o2 ] 352.23968 , found 352.23972 .
the 
 title compound was synthesized according to the general procedure 
 employing 1i ( 0.12 mmol , 33.8 mg ) , 1 mol % ( 1.1 mg ) of 
 pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product was 
 purified by flash column chromatography : yield 73% ( 25 mg ) ; anti / syn 1:1 ; h nmr ( 600 mhz , 
 cdcl3 )  7.367.14 ( m , 10h ) , 6.956.77 
 ( m , 6h ) , 4.484.47 ( m , 2h ) , 4.29 ( dd , j = 
 11.1 , 2.7 hz , 1h ) , 4.22 ( ddd , j = 10.7 , 3.7 , 1.2 
 hz , 1h ) , 4.154.04 ( m , 6h ) , 2.88 ( dd , j = 
 13.7 , 8.4 hz , 1h ) , 2.70 ( dd , j = 14.0 , 7.0 hz , 1h ) , 
 2.68 ( dd , j = 13.7 , 7.2 hz , 1h ) , 2.59 ( dd , j = 13.9 , 8.5 hz , 1h ) , 2.352.29 ( m , 1h ) , 2.22 ( dqd , j = 12.9 , 4.3 , 2.8 hz , 1h ) , 1.97 ( bs , 2h ) , 1.471.45 
 ( m , 6h ) ; c nmr ( 151 mhz , cdcl3 )  147.6 , 
 147.5 , 144.1 , 144.0 , 139.2 , 139.1 , 129.1 ( 2c ) , 128.5 ( 2c ) , 126.3 ( 2c ) , 
 125.0 , 124.0 , 121.8 , 121.6 , 120.4 , 120.1 , 112.6 ( 2c ) , 67.4 , 65.4 , 
 65.2 , 64.7 , 64.4 , 64.3 , 41.3 , 39.8 , 34.6 , 32.9 , 14.8 ( 2c ) ; ft - ir max(atr ) cm 3506 , 2921 , 1585 , 1478 , 1391 , 
 1315 , 1255 , 1214 , 1080 , 1030 , 964 , 900 , 737 ; m / z ( ei ) 284 ( [ m ] , 23 ) , 91 ( [ phch2 ] , 100 ) ; hrms ( ei ) calcd for [ c18h20o3 ] 284.14070 , found 284.14077 .
the 
 title compound was synthesized according to the general procedure 
 employing 1j ( 0.12 mmol , 32.2 mg ) , 1 mol % ( 1.1 mg ) of 
 pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product was 
 purified by flash column chromatography : yield 65% ( 21 mg ) ; mp = 112113 
 c ; anti / syn 1:1 ; h nmr ( 400 mhz , cd3od )  7.307.13 ( m , 10h ) , 
 6.88 ( d , j = 3.0 hz , 1h ) , 6.806.63 ( m , 5h ) , 
 4.46 ( d , j = 3.5 hz , 1h ) , 4.36 ( d , j = 4.6 hz , 1h ) , 4.09 ( dd , j = 11.0 , 2.7 hz , 1h ) , 
 3.993.89 ( m , 2h ) , 3.84 ( ddd , j = 11.0 , 5.1 , 
 0.7 hz , 1h ) , 3.73 ( s , 3h ) , 3.70 ( s , 3h ) , 2.87 ( dd , j = 13.6 , 7.2 hz , 1h ) , 2.74 ( dd , j = 13.7 , 6.2 hz , 
 1h ) , 2.56 ( dd , j = 13.6 , 8.3 hz , 1h ) , 2.47 ( dd , j = 13.7 , 9.3 hz , 1h ) , 2.232.15 ( m , 1h ) , 2.142.07 
 ( m , 1h ) ; c
nmr ( 101 mhz , cd3od )  153.7 , 
 153.4 , 148.2 , 148.1 , 139.7 , 139.5 , 128.8 , 128.7 , 128.0 ( 2c ) , 125.8 , 
 125.7 , 124.9 , 123.9 , 116.7 ( 2c ) , 115.5 ( 2c ) , 113.9 , 113.8 , 67.1 , 64.8 , 
 64.5 ( 2c ) , 54.7 ( 2c ) , 42.0 , 40.7 , 34.3 , 32.3 ; ft - ir max(atr ) cm 2923 , 2471 , 1490 , 1430 , 1265 , 1205 , 
 1161 , 1037 , 807 , 703 ; m / z ( ei ) 270 
 ( [ m ] , 71 ) , 91 ( [ phch2 ] , 33 ) ; hrms 
 ( ei ) calcd for [ c17h18o3 ] 270.12505 , found 270.12551 .
the title 
 compound was synthesized 
 according to the general procedure employing 1k ( 0.12 
 mmol , 32.2 mg ) , 2.5 mol % ( 2.74 mg ) of pc 3 , and 2.5 
 equiv of dipea ( 38.8 mg ) .
the product was purified by flash column 
 chromatography : yield 92% ( 29.8 mg ) ; mp = 100103 c ; anti / syn 1.7:1 ; h nmr ( 400 
 mhz , cd3od )  7.427.21 ( m , 7.2h ) , 7.207.12 
 ( m , 8h ) , 7.09 ( d , j = 8.5 hz , 1h ) , 6.51 ( dd , j = 8.5 , 2.5 hz , 1.7  1h , anti ) , 
 6.44 ( dd , j = 8.5 , 2.5 hz , 1h , syn ) , 6.35 ( d , j = 2.5 hz , 1.7  1h , anti ) , 6.30 ( d , j = 2.5 hz , 1h , syn ) , 4.41 ( d , j = 3.1 hz , 1h , syn ) , 4.34 ( d , j = 3.9 hz , 1.7  1h , anti ) , 4.15 ( dd , j = 11.0 , 2.6 hz , 1.7  1h , anti ) , 4.113.93 ( m , 2h , syn ) , 3.89 
 ( ddd , j = 11.0 , 4.2 , 0.9 hz , 1.7  1h , anti ) , 3.72 ( s , 3h , anti ) , 3.69 ( s , 3h , syn ) , 2.85 ( dd , j = 13.6 , 7.4 hz , 1h , syn ) , 2.66 ( dd , j = 13.7 , 6.6 hz , 1.7  
 1h , anti ) , 2.57 ( dd , j = 13.6 , 8.0 
 hz , 1h , syn ) , 2.46 ( dd , j = 13.7 , 
 9.1 hz , 1.7  1h , anti ) , 2.232.14 ( m , 
 1h , syn ) , 2.142.03 ( m , 1.7  1h , anti ) ; c nmr ( 101 mhz , cd3od )  
 160.7 ( 2c ) , 155.2 ( 2c ) , 139.6 , 139.5 , 131.1 , 130.9 , 128.8 , 128.7 , 
 128.0 ( 2c ) , 125.8 , 125.7 , 117.1 , 115.6 , 107.3 , 106.8 , 100.5 ( 2c ) , 
 66.3 , 64.5 , 64.2 , 64.1 , 54.3 , 54.2 , 42.0 , 40.7 , 34.2 , 32.6 ; ft - ir 
 max(atr ) cm : 3215 , 2960 , 1737 , 
 1667 , 1494 , 1366 , 1221 , 1092 , 1032 , 734 ;
m / z ( ei ) 270 ( [ m ] , 15 ) , 91 ( [ phch2 ] , 89 ) ; hrms ( ei ) calcd for [ c17h18o3 ] 270.12505 , found 270.12534 .
the title 
 compound was synthesized 
 according to the general procedure employing 1l ( 0.12 
 mmol , 32.2 mg ) , 2.5 mol % ( 2.74 mg ) of pc 3 , and 2.5 
 equiv of dipea ( 38.8 mg ) .
the product was purified by flash column 
 chromatography : yield 55% ( 17.7 mg ) ; mp = 121126 c ; anti / syn 1.2:1 ; h nmr ( 600 
 mhz , cdcl3 )  7.32 ( dd , j = 7.6 , 
 1.4 hz , 1.2  1h , anti ) , 7.257.17 ( m , 
 5.4h ) , 7.117.08 ( m , 1.2  1h , anti ) , 
 6.95 ( td , j = 7.5 , 0.9 hz , 1.2  1h , anti ) , 6.916.82 ( m , 7.4h ) , 4.50 ( t , j = 3.5 hz , 1h , syn ) , 4.48 ( t , j = 4.1 hz , 1.2  1h , anti ) , 4.21 ( dd , j = 9.2 , 4.6 hz , 1.2  1h , anti ) 4.114.06 
 ( m , 2h , syn ) , 3.97 ( dd , j = 11.0 , 
 4.0 hz , 1.2  1h , anti ) , 3.80 ( s , 3h , syn ) , 3.79 ( s , 1.2  3h , anti ) , 2.82 
 ( dd , j = 13.8 , 8.5 hz , 1h , syn ) , 
 2.682.58 ( m , 2.2h ) , 2.48 ( dd , j = 14.0 , 9.3 
 hz , 1.2  1h , anti ) , 2.322.24 ( m , 1h , syn ) , 2.212.14 ( m , 1.2  1h , anti ) , 1.91 ( bs , 1.2  1h , anti ) , 1.72 ( bs , 1h , syn ) ; c nmr ( 151 mhz , cdcl3 )  
 158.1 ( 2c ) , 154.3 , 154.2 , 131.1 , 131.0 , 130.1 ( 2c ) , 130.0 ( 2c ) , 129.9 , 
 129.7 , 124.2 , 123.2 , 120.9 , 120.5 , 116.9 ( 2c ) , 114.0 , 113.9 , 67.6 , 
 65.0 , 64.9 , 64.6 , 55.3 ( 2c ) , 41.6 , 40.1 , 33.7 , 31.9 ; ft - ir max(atr ) cm : 3392 , 2928 , 1609 , 1582 , 1510 , 
 1486 , 1450 , 1298 , 1246 , 1176 , 1031 , 850 , 813 , 753 ; m / z ( ei ) 270 ( [ m ] , 27 ) , 121 ( [ 4-meophch2 ] , 100 ) ; hrms ( ei ) calcd for [ c17h18o3 ] 270.12505 , found 270.12548 .
the title 
 compound was synthesized according to the general procedure employing 1 m ( 0.12 mmol , 37.7 mg ) , 1 mol % ( 1.1 mg ) of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product was purified by flash 
 column chromatography : yield 86% ( 32.7 mg ) ; anti / syn 1.8:1 ; h nmr ( 600 mhz , cdcl3 ) 
  7.43 ( d , j = 7.2 hz , 2h ) , 7.39 ( d , j = 7.2 hz , 2h ) , 7.357.18 ( m , 26.7h ) , 7.127.09 
 ( m , 3h ) , 6.976.85 ( m , 5.5h ) , 4.44 ( bs , 1h , syn ) , 4.41 ( bs , 1.8  1h , anti ) , 4.27 ( dd , j = 11.2 , 2.3 hz , 1.8  1h , anti ) , 
 4.144.06 ( m , 2h , syn ) , 4.00 ( ddd , j = 10.8 , 3.5 , 1.5 hz , 1h , syn ) , 3.963.93 
 ( m , 1.8  1h , anti ) , 3.70 ( d , j = 12.4 hz , 1.8  1h , anti ) , 2.91 ( ddd , j = 11.9 , 7.5 , 3.2 hz , 1h , syn ) , 2.79 ( dq , j = 12.4 , 2.3 hz , 1.8  1h , anti ) , 
 2.00 ( bs , 1.8  1h , anti ) , 1.80 ( bs , 1h , syn ) ; c nmr ( 151 mhz , cdcl3 )  154.4 ( 2c ) , 142.6 , 
 142.4 , 142.3 ( 2c ) , 130.9 , 130.5 , 130.0 , 129.9 , 128.9 ( 2c ) , 128.8 ( 2c ) , 
 128.1 ( 2c ) , 127.9 , 127.8 , 126.8 , 126.7 , 126.6 , 126.6 , 124.0 , 122.5 , 
 121.0 , 120.5 , 117.1 , 116.9 , 65.8 , 64.1 , 64.0 , 63.1 , 49.6 , 49.2 , 43.0 , 
 41.9 ; ft - ir max(atr ) cm : 3036 , 
 2927 , 1702 , 1619 , 1516 , 1491 , 1446 , 1318 , 1226 , 1117 , 1014 , 972 , 755 ; m / z ( ei ) 167 ( [ chph2 ] , 59 ) , 151 ( [ m  cph2 ] , 28 ) ; hrms ( ei ) 
 calcd for [ c22h20o2 ] 316.14578 , 
 found 316.14636 .
the title compound was synthesized according 
 to the general 
 procedure employing 1n ( 0.12 mmol , 26.7 mg ) , 2.5 mol 
 % ( 2.74 mg ) of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) . 

the product was purified by flash column chromatography : yield 68% 
 ( 14.6 mg ) ; anti / syn 2.5:1 ; h nmr ( 600 mhz , cdcl3 )  7.417.35 
 ( m , 4h ) , 7.357.29 ( m , 10h ) , 7.287.21 ( m , 14.5h ) , 7.197.15 
 ( m , 3h ) , 5.00 ( d , j = 5.4 hz , 1h , syn ) , 4.95 ( d , j = 6.6 hz , 2.5  1h , anti ) , 3.143.07 ( m , 4.5h ) , 3.01 ( dd , j = 15.3 , 
 7.3 hz , 3h ) , 2.872.83 ( m , 2.5h ) , 2.812.75 ( m , 4h ) , 
 2.68 ( dq , j = 14.0 , 7.9 hz , 1h , syn ) , 2.622.48 ( m , 6h ) , 1.62 ( bs , 3.5h ) ; c nmr 
 ( 151 mhz , cdcl3 )  144.7 , 144.5 , 143.5 , 141.5 , 141.2 , 
 140.6 , 128.9 ( 2c ) , 128.7 , 128.5 , 128.4 , 128.2 , 126.8 ( 2c ) , 126.2 , 
 125.9 , 125.0 , 124.8 , 124.7 , 123.9 , 80.8 , 76.3 , 52.3 , 46.9 , 39.3 , 35.9 , 
 35.8 , 35.0 ; ft - ir max(atr ) cm 3363 , 2932 , 1487 , 1454 , 1257 , 1102 , 1026 , 804 , 745 , 697 ; m / z ( ei ) 223 ( [ m  1 ] , 21 ) , 132 ( m  [ phch2 ] , 100 ) 91 ( [ phch2 ] , 80 ) ; hrms ( ei ) calcd for [ c16h16o ] 224.11957 , found 224.11989 .
the title compound was synthesized according 
 to the general procedure 
 employing 1o ( 0.12 mmol , 30 mg ) , 2.5 mol % ( 2.74 mg ) 
 of pc 3 , and 2.5 equiv of dipea ( 38.8 mg ) .
the product 
 was purified by flash column chromatography : yield 59% ( 17.7 mg ) ; e / z 1:1 ; h nmr ( 400 mhz , cdcl3 )  7.41 ( dd , j = 7.7 , 1.6 hz , 1h ) , 
 7.317.18 ( m , 6h ) , 7.167.07 ( m , 2h ) , 7.067.00 
 ( m , 2h ) , 7.036.8 ( m , 6h ) , 6.77 ( s , 1h ) , 5.32 ( s , 1h ) , 5.19 
 ( s , 1h ) , 4.974.86 ( m , 3h ) , 4.57 ( dd , j = 
 12.0 , 0.9 hz , 1h ) , 2.37 ( s , 3h ) , 2.35 ( s , 3h ) , 2.14 ( bs , 1h ) , 2.05 
 ( bs , 1h ) ; c nmr ( 101 mhz , cdcl3 )  154.4 , 
 154.3 , 138.1 ( 2c ) , 135.5 , 135.4 , 134.4 , 133.4 , 131.6 , 130.3 , 130.0 , 
 129.8 , 129.5 ( 2c ) , 129.2 , 129.0 , 128.7 , 128.4 , 128.3 ( 2c ) , 125.9 , 
 125.8 , 124.9 , 124.0 , 121.1 ( 2c ) , 117.2 , 116.9 , 69.3 , 68.1 , 63.0 , 62.8 , 
 21.4 ( 2c ) ; ft - ir max(atr ) cm 3391 , 2922 , 1737 , 1590 , 1479 , 1370 , 1224 , 993 , 921 , 756 , 702 ; m / z ( ei ) 252 ( [ m ] , 17 ) , 104 
 ( [ 3-meph ] , 25 ) , 91 ( [ 3-mephch ] , 32 ) ; hrms 
 calcd for [ c17h16o2 ] 252.11448 , 
 found 252.11402 .
the title compound 
 was synthesized 
 according to the general procedure employing 1p ( 0.12 
 mmol , 32 mg ) , 2.5 mol % ( 2.74 mg ) of pc 3 , and 2.5 equiv 
 of dipea ( 38.8 mg ) .
the product was purified by flash column chromatography : 
 yield 57% ( 18.3 mg ) , e / z 1:1 ; h nmr ( 600 mhz , cdcl3 )  7.467.43 
 ( m , 2h ) , 7.427.39 ( m , 1h ) , 7.307.28 ( m , 1h ) , 7.247.20 
 ( m , 2h ) , 7.207.16 ( m , 2h ) , 6.996.84 ( m , 9h ) , 6.76 
 ( s , 1h ) , 5.33 ( s , 1h ) , 5.18 ( s , 1h ) , 4.994.89 ( m , 2h ) , 4.87 
 ( dd , j = 12.0 , 1.2 hz , 1h ) , 4.594.55 ( m , 
 1h ) , 3.83 ( s , 3h ) , 3.82 ( s , 3h ) , 2.20 ( bs , 1h ) , 2.07 ( bs , 1h ) ; c nmr ( 151 mhz , cdcl3 )  159.3 , 159.1 , 154.4 , 
 154.3 , 133.3 , 133.2 , 131.9 , 131.3 , 130.3 , 130.2 , 130.0 , 129.8 , 129.1 , 
 128.8 , 128.1 , 128.0 , 125.0 , 124.1 , 121.1 ( 2c ) , 117.3 , 116.9 , 113.9 
 ( 2c ) , 69.4 , 68.2 , 63.0 , 62.8 , 55.3 ( 2c ) ; ft - ir max(atr ) cm 3393 , 2958 , 2929 , 1606 , 1509 , 1485 , 
 1458 , 1246 , 1177 , 1031 , 995 , 828 , 755 ; m / z ( ei ) 268 ( [ m ] , 25 ) , 120 ( [ 3-meophch ] , 100 ) .
 a visible 
 light photoredox - catalyzed aldehyde olefin cyclization 
 is reported . 
 the method represents a formal hydroacylation of alkenes 
 and alkynes and provides chromanol derivatives in good yields . 
 the 
 protocol takes advantage of the double role played by trialkylamines 
 ( nr3 ) which act as ( i ) electron donors for reducing the 
 catalyst and ( ii ) proton donors to activate the substrate via a proton - coupled 
 electron transfer . 
Conclusions
Experimental Section