Reduction of lactones 1, which were prepared by the previously disclosed methods , with {HEAD ~ DIBAL H} followed by {TAIL ~ acid catalyzed methylation} provides lactal intermediates 2 
followed by
Reduction of lactones 1 , which were prepared by the previously disclosed methods , with { HEAD ~ DIBAL H } followed by { TAIL ~ acid catalyzed methylation } provides lactal intermediates 2
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH