Alkenyl Carbonyl Derivatives in Enantioselective Redox Relay Heck Reactions: Accessing α,β-Unsaturated Systems
摘要:
A highly enantioselective and site-selective Pd-catalyzed arylation of alkenes linked to carbonyl derivatives to yield alpha,beta-unsaturated systems is reported. The high site selectivity is attributed to both a solvent effect and the polarized nature of the carbonyl group, both of which have been analyzed through multidimensional analysis tools. The reaction can be performed in an iterative fashion allowing for a diastereoselective installation of two aryl groups along an alkyl chain.
A gas chromatographic investigation of the volatile part of a pineapple concentrate led to the identification of 59 substances, 35 of which were not previously found in pineapple. The identifications and syntheses of some esters (Δ3- and Δ4-unsaturated, β-hydroxy, β-acetoxy, and δ-acetoxy) and of a new sulfur compound are given.
Pheromone, XXXII. Bausteine zur Darstellung zweifach ungesättigter Schmetterlings-pheromone
作者:Hans Jürgen Bestmann、Karl Heinrich Koschatzky、Wilfried Schätzke、Joachim Süß、Otto Vostrowsky
DOI:10.1002/jlac.198119810920
日期:1981.9.21
Die Darstellung α,ω-bifunktioneller Ausgangsverbindungen sowie (Z)- und (E)-konfigurierter, ungesättigter Synthesebausteine, die man mittels Wittig-Reaktion, Michael-Addition, Acetylen-synthese oder Crombie-Reaktion erhält, wird beschrieben. Diese Verbindungen werden im Rahmen eines „Baukastensystems” zur Synthese bisolefinischer Sexualpheromone benötigt.
Transforming Olefins into
<i>γ</i>
,
<i>δ</i>
‐Unsaturated Nitriles through Copper Catalysis
作者:Xuesong Wu、Jan Riedel、Vy M. Dong
DOI:10.1002/anie.201705859
日期:2017.9.11
We have developed a strategy to transform olefins into homoallylic nitriles through a mechanism that combines copper catalysis with alkyl nitrile radicals. The radicals are easily generated from alkyl nitriles in the presence of the mild oxidant di‐tert‐butyl peroxide. This cross‐dehydrogenative coupling between simple olefins and alkylnitriles bears advantages over the conventional use of halides
The conjugate addition of cis- or trans-1-alkenyl-cuprolithium complexes (RCHCH)2CuLi · Xn1 to α, β-unsaturated carbonyl compounds was found to occur with high retention of double bond geometry, affording isomerically pure cis- or trans-γ, δ-ethylenic carbonyl compounds. The same 1-alkenylcuprates also react stereospecifically with alkyl halides to give isomerically pure cis- or trans-olefins.
发现在α,β-不饱和羰基化合物上可以顺式或反式-1-烯基-铜锂复合物(RCHCH)2 CuLi·X n 1的共轭加成反应,可以保持双键几何结构的高度保留,从而提供异构体纯的顺式-或反式-γ,δ-烯属羰基化合物。相同的1-烯基铜酸酯也与卤代烷立体定向反应,得到异构纯的顺式或反式烯烃。
Alkenyl Carbonyl Derivatives in Enantioselective Redox Relay Heck Reactions: Accessing α,β-Unsaturated Systems
作者:Chun Zhang、Celine B. Santiago、Lei Kou、Matthew S. Sigman
DOI:10.1021/jacs.5b04289
日期:2015.6.17
A highly enantioselective and site-selective Pd-catalyzed arylation of alkenes linked to carbonyl derivatives to yield alpha,beta-unsaturated systems is reported. The high site selectivity is attributed to both a solvent effect and the polarized nature of the carbonyl group, both of which have been analyzed through multidimensional analysis tools. The reaction can be performed in an iterative fashion allowing for a diastereoselective installation of two aryl groups along an alkyl chain.