Lipase-mediated deracemization of secondary 1-phenyl-substituted propargylic alcohols of different topology
摘要:
Acetylation of (+/-)-1-phenylnon-2-yn-1-ol, (+/-)-1-phenylhept-1-yn-3-ol, and (+/-)-1-phenylundec-4-yn-3-ol ((+/-)-5) in the presence of lipase from Candida cylindracea (CCL) proceeds slowly to give products with ee less than or equal to20%. The acetates of these alcohols are hydrolyzed in the presence of porcine pancreatic lipase (PPL) equally unsatisfactorily. The (eta(6)-arene)tricarbonylchromium complex of alcohol (+/-)-5 is acetylated in the presence of CCL up to similar to22% conversion to give (R)-acetate whose oxidative decomplexation followed by saponification results in alcohol (R)-(-)-5 with ee greater than or equal to95%. The configuration of alcohols (-)-5 and (+)-5 was determined by NMR spectroscopy of their esters with (R)- and (S)-Mosher's acids.
Lipase-mediated deracemization of secondary 1-phenyl-substituted propargylic alcohols of different topology
摘要:
Acetylation of (+/-)-1-phenylnon-2-yn-1-ol, (+/-)-1-phenylhept-1-yn-3-ol, and (+/-)-1-phenylundec-4-yn-3-ol ((+/-)-5) in the presence of lipase from Candida cylindracea (CCL) proceeds slowly to give products with ee less than or equal to20%. The acetates of these alcohols are hydrolyzed in the presence of porcine pancreatic lipase (PPL) equally unsatisfactorily. The (eta(6)-arene)tricarbonylchromium complex of alcohol (+/-)-5 is acetylated in the presence of CCL up to similar to22% conversion to give (R)-acetate whose oxidative decomplexation followed by saponification results in alcohol (R)-(-)-5 with ee greater than or equal to95%. The configuration of alcohols (-)-5 and (+)-5 was determined by NMR spectroscopy of their esters with (R)- and (S)-Mosher's acids.