Carbonylation of <i>cis</i>-Disubstituted Epoxides to <i>trans</i>-β-Lactones: Catalysts Displaying Steric and Contrasteric Regioselectivity
作者:Michael Mulzer、Geoffrey W. Coates
DOI:10.1021/jo501899e
日期:2014.12.19
trans-beta-Lactones are a versatile and useful class of compounds, but reliable methods for their direct synthesis are still limited. Addressing this problem, we present herein two catalysts for the regioselective carbonylation of cis-disubstituted epoxides. The two catalysts show high activities and opposing regioselectivities so that either one of the two possible beta-lactone regioisomers can be obtained selectively.
Enhancements of enantio and diastereoselectivities in reduction of (Z)-3-halo-4-phenyl-3-buten-2-one mediated by microorganisms in ionic liquid/water biphasic system
作者:Dávila S. Zampieri、Bruno R.S. de Paula、Luiz A. Zampieri、Juliana A. Vale、J. Augusto R. Rodrigues、Paulo J.S. Moran
DOI:10.1016/j.molcatb.2012.08.005
日期:2013.1
Reductions of (Z)-C6H5CH=CXC(=O)CH3 (X=Cl, Br) mediated by Saccharomyces cerevisiae, Candida albicans, Rhodotorula glutinis, Geotrichum candidum and Micrococcus luteus gave the corresponding halohydrins through consecutive reduction reactions of C=C and C=O bonds. In general, the reactions performed in the biphasic system water/[(bmim)PF6] gave better diastereoselectivity and enantioselectivity than in pure water. (C) 2012 Elsevier B.V. All rights reserved.