An Acyl-Claisen Approach to Tetrasubstituted Tetrahydrofuran Lignans: Synthesis of Fragransin A2, Talaumidin, and Lignan Analogues
作者:David Barker、Claire Rye
DOI:10.1055/s-0029-1218363
日期:2009.12
A simple and stereocontrolled synthesis of racemic 2,3,4,5-tetrasubstituted tetrahydrofurans was achieved from acyl-Claisen derived syn-disubstituted amides.
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。
Preparation of Indolenines via Nucleophilic Aromatic Substitution
作者:Florian Huber、Joel Roesslein、Karl Gademann
DOI:10.1021/acs.orglett.9b00489
日期:2019.4.19
An unusual aromatic substitution to access indolenines is described. 2-(2-Methoxyphenyl)acetonitrile derivatives are reacted with various alkyl and aryl Li reagents to furnish the corresponding indolenine products, constituents of natural products, and cyanine dyes such as indocyanine green. This new method was used to synthesize 41 indolenines with large functional group tolerance, and selected examples
Difluoromethyl‐substituted allylicphosphates were synthesized from 2‐cycloalkenones through the addition of a (difluoromethyl)phosphonate and subsequent phospha‐Brook rearrangement. The obtained allylicphosphates were converted to the corresponding difluoromethyl‐substituted cycloalkenes using the Cu‐mediated SN2’ reaction of Grignard or organolithium reagents.
通过添加(二氟甲基)膦酸酯和随后的Pha-Brook重排,由2-环烯酮合成二氟甲基取代的烯丙基磷酸酯。使用格氏试剂或有机锂试剂的Cu介导的S N 2'反应,将获得的烯丙基磷酸酯转化为相应的二氟甲基取代的环烯烃。
Highly Diastereoselective Conjugate Addition of Aryllithium to Chiral β-Nitrostyrene Derivative: An Application to the Asymmetric Synthesis of 4-Aryl-1,2,3,4-tetrahydroisoquinoline
Highlydiastereoselectiveconjugateaddition of aryllithium to β-nitrostyrene derivative, having chiral acetal moiety derived from (S,S)-1,2-bis(1-hydroxypropyl)benzene, was achieved. The adduct wa...