Environmentally friendly, efficient resolution of racemic secondary alcohols by lipase-catalyzed enantioselective transesterification in ionic liquids in the presence of organic bases.
The lipase-catalyzed enantioselective transesterification of racemic secondary alcohols was studied using vinyl acetate as acyl donor in two imidazolium-based ionic liquids vs. hexane (Scheme), both in the absence and presence of catalytic amounts of organic bases such as triethylamine (Et(3)N) or pyridine. The organic bases generally enhanced both the rate and enantioselectivity of the reaction. Further, the system 1-butyl-3-methyl-1H-imidazolium hexafluorophosphate/Candida antarctica lipase B ([bmim][PF(6)]/CALB) could be readily recycled four times without significant loss in activity or enantioselectivity.
Wu
Xiao-Mei
XM
State Key Laboratory for Oxo Synthesis & Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, PR China.
Xin
Jia-Ying
JY
Sun
Wei
W
Xia
Chun-Gu
CG
D000438:Alcohols / Q000737:chemistry*; D002175:Candida / Q000201:enzymology; D002384:Catalysis; D008049:Lipase / Q000378:metabolism*; D013237:Stereoisomerism
D000438:Alcohols; D008049:Lipase