Syntheses of Highly Substituted Enantiopure C6 and C7 Enones1
摘要:
Enantiopure epoxyvinyl sulfones SS-9a, SS-9b, produced from Jacobsen epoxidation of 2-phenylsulfonyl 1,3-cyclohexa- and cycloheptadiene, are used as a template for the construction of substituted cycloalkenones and as chiral synthetic equivalents of enones a and b. The addition of carbon nucleophiles to SS-9a, SS-9b is high yielding and stereospecific. Enantiopure alpha,beta- and gamma-substituted cycloalkenones are easily constructed using a variety of methods.
The invention provides novel six and seven-carbon termini-differentiated polypropionate stereotetrads and stereopentads useful in syntheses of natural products. The invention also provides a novel alkylative sulfenylation-desulfonylation process that efficiently transforms enantiopure epoxyvinyl sulfones to syn and anti dienylsulfides in two operations.
Enantioselective Synthesis of Functionalized Nitrocyclopropanes by Organocatalytic Conjugate Addition of Bromonitroalkanes to α,β-Unsaturated Enones
作者:Jian Lv、Jiaming Zhang、Zhu Lin、Yongmei Wang
DOI:10.1002/chem.200801651
日期:2009.1.12
A general enantioselective synthesis of functionalized nitrocyclopropanes by organocatalytic conjugateaddition of a variety of bromonitroalkanes to α,β‐unsaturated enone systems is presented. The process, efficiently catalyzed by the salts of 9‐amino‐9‐deoxyepiquinine 1 d serves as a powerful approach to the preparation of synthetically and biologically important cyclopropanes with high levels of
Catalytic Desymmetrizing Dehydrogenation of 4-Substituted Cyclohexanones through Enamine Oxidation
作者:Lihui Zhu、Long Zhang、Sanzhong Luo
DOI:10.1002/anie.201713327
日期:2018.2.19
A desymmetrizing dehydrogenation process catalyzed by a chiral primary amine is described herein. The reaction proceeds through the oxidation of a ketone enamine by IBX and enables the highly enantioselective desymmetrization of 4‐substituted cyclohexanones with the generation of chiral 4‐substituted cyclohexenones containing a remote γ‐stereocenter.
Lithium N-trityl-N-(R)-1-phenethylamide, a readily available and useful base for the enantioselective formation of chiral enolates from achiral ketones
作者:Jakub Busch-Petersen、E.J Corey
DOI:10.1016/s0040-4039(00)01185-0
日期:2000.9
Lithium N-trityl-N-(R)-1-phenylethylamide (6) is a readily available and useful reagent for the enantioselective (20:1) conversion of 4-t-butylcyclohexanone to the corresponding (S)-enolate. This reaction provides access to numerous useful chiral compounds. (C) 2000 Elsevier Science Ltd. All rights reserved.