1206614-89-2Relevant articles and documents
Stereochemical course of baker's yeast mediated reduction of the tri- and tetrasubstituted double bonds of substituted cinnamaldehydes
Fronza, Giovanni,Fuganti, Claudio,Serra, Stefano
experimental part, p. 6160 - 6171 (2010/03/24)
A comprehensive study of the stereochemical course of baker's yeast mediated reduction of substituted cinnamaldehydes is reported. Hydride addition to the β position of β-methylcinnamaldehydes preferentially afforded isomers of (3S)-3-phenylbutan-1-ol. The reduction of (E)-2,3-dimethyl- cinnamaldehyde (15) produced a mixture of (2S,3S)- and (2R,3S)-2-methyl-3- phenylbutan-1-ol (13 and 14), respectively, with 93 % ee. Conversely (Z)-2,3-dimethylcinnamal-dehyde (16) afforded, a mixture of 13 and 14 with 33 % ee. Accordingly, the reduction of trisubstituted β-methylcinnam-aldehydes 34 and 35 proceeded with the same stereochemical preference and with higher enantioselectivity to give (S) 3-phenylbutan-1-ol (37). In addition, deuterium, incorporation and 2H NMR studies demonstrated that the addition of the second hydrogen atom to the a position proceeded with very low stereochemical control and the overall process is formally a mixture of cis/trans hydrogen addition to the double bond. Alternatively, α-methylcinnamaldehyde is reduced to (S)-2-methyl-3-phenylpropan-1-ol (24) with preferential addition of the hydride to the opposite β face with good stereochemical control of the irons addition of hydrogen to the double bond. Wiley-VCH Verlag GmbH & Co. KGaA.
