acoh ( 3.00 mmol ) was added to a solution of galactoside 20 or 13 ( 1.57 mmol ) in acetone ( 3.5 ml ) and meoh ( 4.7 ml ) at 0 c .
after 8 h , the reaction was quenched by the addition of nahco3 ( 5.95 mmol ) and then filtered .
after concentration of the filtrate under reduced pressure , the resulting oil was purified by flash column chromatography ( etoac in hexane ) to afford alcohol 21 ( from 20 ) or 26 ( from 13 ) as a colorless oil .
pph3 ( 1.86 mmol ) , diad ( 1.86 mmol ) , and dppa ( 1.86 mmol ) were added sequentially to a cooled solution of alcohol 21 or 26 ( 0.90 mmol ) in thf ( 20 ml ) .
concentration under reduced pressure followed by purification of the residue by flash column chromatography ( etoac in hexane ) afforded azide 22 ( from 21 ) or 25 ( from 26 ) as a colorless oil .
tfa ( 0.50 ml , 6.6 mmol ) was added dropwise over 5 min to a solution of azide 22 ( 200 mg , 0.19 mmol ) in ch2cl2 ( 5 ml ) at rt .
after 30 min , the reaction mixture was concentrated under reduced pressure to afford pentaol 9 as a colorless oil ( 115 mg , quant . ) : [ ]d + 12.4 ( c 0.5 , cdcl3:cd3od , 2:1 ) ; max(film ) ( cm ) 3282s br ( oh ) , 2114s ( n3 ) , 1696 m ( c = o ) ; h nmr ( 300 mhz , cdcl3:cd3od , 2:1 ) 0.85 ( t , j = 6.0 hz , 3h ) , 1.181.39 ( stack , 22h ) , 1.401.71 ( stack , 4h ) , 1.44 ( s , 9h ) , 3.26 ( a of abx , jab = 12.6 hz , jax = 4.9 hz , 1h ) , 3.513.64 ( stack , 3h ) , 3.653.98 ( stack , 7h ) , 4.89 ( d , j = 3.3 hz , 1h ) ; c nmr ( 100 mhz , cdcl3:cd3od , 2:1 ) 14.3 ( ch3 ) , 23.2 ( ch2 ) , 26.4 ( ch2 ) , 28.6 ( ch3 ) , [ 29.9 , 30.2 , 32.4 , 32.8 ( ch2 , resonance overlap ) ] , 51.7 ( ch ) , 51.8 ( ch2 ) , 68.3 ( ch2 ) , 69.3 ( ch ) , 70.4 ( ch ) , 70.6 ( 2  ch , resonance overlap ) , 72.5 ( ch ) , 75.3 ( ch ) , 80.1 ( c ) , 156.8 ( c ) ; ms ( tof es+ ) m / z 627.3 ( [ m + na ] , 100% ) ; hrms ( tof es+ ) calcd for c29h56n4o9na [ m + na ] 627.3945 , found 627.3956 .
tfa ( 1.0 ml , 13.2 mmol ) was added dropwise over 5 min to azide 22 ( 400 mg , 0.38 mmol ) at rt .
the resulting colorless oil was used in the next step without further purification ( 192 mg , quant . ) .
tfa ( 0.50 ml , 6.6 mmol ) was added dropwise over 5 min to azide 9 ( 114 mg , 0.19 mmol ) at rt .
the resulting colorless oil was used in the next step without further purification ( 96 mg , quant . ) .
 a concise route to the 6-azido-6-deoxy--galactosyl - phytosphingosine derivative 9 is reported . 
 orthogonal protection of the two amino groups allows elaboration of 9 into a range of 6-n - derivatized -galactosyl ceramides by late - stage introduction of the acyl chain of the ceramide and the 6-n - group in the sugar headgroup . 
 biologically active glycolipids 6 and 8 have been synthesized to illustrate the applicability of the approach . 
Experimental Section