SYNTHESIS OF (-)-(ACETOXYMETHYL)(HYDROXYM ETHYL)METHYL(PHENYL)GERMANE[(-)-MEPHGE(CH2OAC)(CH2OH)] BY AN ESTERASE-CATALYZED TRANSESTERIFICATION - THE 1ST ENZYMATIC-SYNTHESIS OF AN OPTICALLY-ACTIVE GERMANE
R. Tacke et al., SYNTHESIS OF (-)-(ACETOXYMETHYL)(HYDROXYM ETHYL)METHYL(PHENYL)GERMANE[(-)-MEPHGE(CH2OAC)(CH2OH)] BY AN ESTERASE-CATALYZED TRANSESTERIFICATION - THE 1ST ENZYMATIC-SYNTHESIS OF AN OPTICALLY-ACTIVE GERMANE, Chemische Berichte, 127(4), 1994, pp. 639-642
The prochiral germane MePhGe(CH2OH)2 (1) was synthesized by a six-step
synthesis starting from GeCl4 (3) [3 --> Cl2Ge(CH2Cl)2 (4) --> Ph2Ge(
CH2Cl)2 (5) --> (CF3S(O)2O)Ph-Ge(CH2Cl)2 (6) --> MePhGe(CH2Cl)2 (7) --
> MePhGe-(CH2OAc)2 (8) --> 1]. Reaction of 1 with Ac2O/NEt3 (molar rat
io 1: Ac2O = 1:1) gave the racemic germane rac-MePhGe(CH2OAc)(CH2OH) (
rac-2). Stereoselective transesterification of 1 with vinyl acetate (a
cetate source and solvent), catalyzed by immobilized porcine liver est
erase (PLE; E.C.-3.1.1.1), yielded the optically active germane (-)-Me
PhGe(CH2OAc)(CH2OH) [(-)-2] (yield 57%, enantiomeric purity 50% ee).