Copper-catalyzed Z-selective semihydrogenation of alkynes with hydrosilane: a convenient approach to cis-alkenes
摘要:
A copper catalyst generated in situ from widely available copper salt and imidazolium salt in the presence of t-BuOK showed high efficiency for the semihydrogenation of a wide range of internal and terminal alkynes to their corresponding alkenes without obvious over-reduction. Functional groups, such as hydroxyl, nitro, halides, and amino, etc. were tolerated. The Z/E ratios of the obtained alkenes were generally >99%. Finally, semireduction of bulky alkynes also went smoothly. (C) 2014 Elsevier Ltd. All rights reserved.
addition of alkylcopper compounds to 1-alkynes, are transformed with retention to various ethylenic structures; 1-deutero-1-alkenes, symmetrical conjugated dienes, 1-iodo-1-alkenes, di- or tri-substituted alkenes and primary or secondary allylic alcohols.
group, readily undergo the ZACAreaction with Me3Al and higher alkylalanes in a 1:1 molar ratio in the presence of a catalytic amount (1–5 mol %) of bis[(1-neomenthyl)indenyl]zirconium dichloride in good yields and in good enantioselectivity (70–92% ee), thereby providing an efficient and convenient route to various alkene-containing chiral natural products. Only the reaction of the parent 1,4-pentadiene
A copper catalyst generated in situ from widely available copper salt and imidazolium salt in the presence of t-BuOK showed high efficiency for the semihydrogenation of a wide range of internal and terminal alkynes to their corresponding alkenes without obvious over-reduction. Functional groups, such as hydroxyl, nitro, halides, and amino, etc. were tolerated. The Z/E ratios of the obtained alkenes were generally >99%. Finally, semireduction of bulky alkynes also went smoothly. (C) 2014 Elsevier Ltd. All rights reserved.
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.