Preparation of enantiomerically enriched aromatic β-hydroxynitriles and halohydrins by ketone reduction with recombinant ketoreductase KRED1-Pglu
作者:Martina L. Contente、Immacolata Serra、Francesco Molinari、Raffaella Gandolfi、Andrea Pinto、Diego Romano
DOI:10.1016/j.tet.2016.05.027
日期:2016.7
A NADPH-dependent benzil reductase (KRED1-Pglu) was used as recombinant enzyme for catalysing the reduction of different functionalised ketones. The reactions were carried out in the presence of a catalytic amount of NADP+ and an enzyme-coupled transformation (oxidation of glucose catalysed by glucose dehydrogenase), for regenerating the cofactor and thus driving the reaction to completion. KRED1-Pglu
Phase-transfer alkylation in a microreactor proceeds smoothly, and the reaction has been found to be more efficient than that in a round-bottomed flask with vigorous stirring; we have observed by an optical microscope study that an interfacial area provided by organic and aqueous phases is more extended in a microreactor.
highly efficient electrophilic cyanation of boron enolates using readily available cyanating reagents, N‐cyano‐N‐phenyl‐p‐toluenesulfonamide (NCTS) and p‐toluenesulfonyl cyanide (TsCN), is reported. Various β‐ketonitriles were prepared by this new protocol, which has a remarkably broad substrate scope compared to existing methods. The present method also allowed efficient synthesis of β‐ketonitriles containing
organolithiums, Grignardreagents, or zincates to sulfinylnitriles triggers a facile sulfinyl–metal exchange to afford N‐ or C‐metalated nitriles. Sulfinyl–magnesium exchange–alkylations efficiently install quaternary and tertiary centers, even in the case of tertiary sulfinylnitriles that contain a highly acidic methine proton. α‐Sulfinylalkenenitriles afford moderately nucleophilic magnesiated nitriles, and
This paper describes the direct synthesis of pyrazoles fromesters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield [small beta]-ketonitrile or [small alpha],[small beta]-alkynone intermediates, and condensation by hydrazine addition....