Although yeast reduction of α-diketones 1 affords a mixture of two α-hydroxy ketones and a vic-diol, the use of methyl vinyl ketone as an enzyme inhibitor prevents the production of the diol. Regioselectivity in the reduction to afford α-hydroxy ketones is improved by thermal pre-treatment of baker's yeast. Thus, 1-phenyl-2-hydroxy-1-propanone 3a is obtained in 80 % yield with >98% e.e.
α-Hydroxylation of α,α-Disubstituted <i>N</i>-<i>tert</i>-Butanesulfinyl Ketimines with Molecular Oxygen: Stereoselective Synthesis of α-Tertiary Hydroxyimines
作者:Nuermaimaiti Yisimayili、Hui Liu、Yun Yao、Chong-Dao Lu
DOI:10.1021/acs.orglett.1c04198
日期:2022.1.21
α-Tertiary hydroxyimines were stereoselectively synthesized from enantioenriched N-tert-butanesulfinyl ketimines using potassium tert-butoxide, molecular oxygen, and trimethyl phosphite. The stereoselective hydroxylation of acyclic ketimines bearing two sterically similar α-substituents was achieved by controlling the geometry of the metalloenamine intermediates and the facial selectivity of hydroxylation
Biocatalytic Route to Chiral Acyloins: P450-Catalyzed Regio- and Enantioselective α-Hydroxylation of Ketones
作者:Rubén Agudo、Gheorghe-Doru Roiban、Richard Lonsdale、Adriana Ilie、Manfred T. Reetz
DOI:10.1021/jo502397s
日期:2015.1.16
monooxygenase generated by directed evolution are excellent catalysts for the oxidative α-hydroxylation of ketones with formation of chiral acyloins with high regioselectivity (up to 99%) and enantioselectivity (up to 99% ee). This constitutes a new route to a class of chiral compounds that are useful intermediates in the synthesis of many kinds of biologically active compounds.