achieved with a two-step protocol comprising an allylic cation mediated nucleophilic addition and an intramolecular cyclization reaction. The N-aryl sulfonyl protecting groups of cyclization products were readily removed to furnish free amines with retention of halogensubstitutions and CC double bonds.
In this study, a novel asymmetricsynthesis of all-carbon quaternary stereogeniccentres is developed by the connection of three prochiral or achiral components--conjugated enones, organometallic compounds and vinyl esters--at the...
with a lipase produced the regio- and enantioconvergent transformation of racemic allyl alcohols (1 or 2) into optically active allyl esters. In this system, the vanadium compounds catalyzed the continuous racemization of the alcohols along with the transposition of the hydroxyl group, while the lipase effected the chemo- and enantioselective esterification to achieve the dynamickineticresolution.
an efficient asymmetric denitrogenative cycloaddition of benzotriazoles with cyclic and acyclic 1,3-dienes enabled by Pd and chiral sulfonamide phosphine ligand. A variety of substituted hexahydrocarbazoles and indolines were delivered in good yields with high ee values. Interestingly, a pair of enantiomers could be obtained with the use of Xu1 and PC2 with the same absolute configuration. The synthetic
不对称脱氮环加成已成为构建手性氮杂杂环的有力工具。然而,迄今为止,仅探索了苯并三唑与不饱和烃的不对称脱氮环加成的一个例子,因为苯并三唑开环生成α-亚氨基金属类卡宾是一种热力学不利的过程。我们在此报告了由 Pd 和手性磺酰胺膦配体实现的苯并三唑与环状和非环状 1,3-二烯的有效不对称脱氮环加成反应。各种取代的六氢咔唑和二氢吲哚均以良好的收率和高 ee 值交付。有趣的是,使用Xu1和PC2可以获得一对对映异构体具有相同的绝对配置。还展示了光学活性六氢咔唑的合成效用。
Scalable and sustainable electrochemical allylic C–H oxidation
作者:Evan J. Horn、Brandon R. Rosen、Yong Chen、Jiaze Tang、Ke Chen、Martin D. Eastgate、Phil S. Baran
DOI:10.1038/nature17431
日期:2016.5.5
transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylicoxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications