A sequential Rh(i)-catalyzed vinylation/[2 + 1]carbocyclization between enynes and diazo compounds has been developed. This transformation features a wide range of enynes and acceptor/acceptor diazo compounds, providing easy access to versatile vinyl-substituted azabicyclo[3.1.0]hexanes having a broad tolerance to functional groups.
of the triplebond results in either cyclopropanation of the double bond with bulky R groups (SiMe3, Ph) or formation of alkylidene-alkenyl five-membered heterocycles, resulting from a beta elimination process, with less bulky R groups (R = Me, CH2CH=CH2). The reaction can be applied to in situ desilylation in methanol and direct formation of vinylbicyclo[3.1.0]hexanes and to the formation of some
在作为催化剂前体的 RuCl(COD)Cp* 存在下,各种含 CCH 键的 1,6-烯炔与 N2CHSiMe3 的反应导致在室温下普遍形成具有高 Z 的链烯基双环 [3.1.0] 己烷- 烯基的立体选择性和烯基的顺式排列和初始双键取代基,对于该双键的 E 构型。立体化学是通过确定三种双环产物的 X 射线结构来建立的。与在三键的 C1 碳上带有 R 取代基的 1,6-烯炔的相同反应导致双键与庞大的 R 基团(SiMe3,Ph)的环丙烷化或形成亚烷基-烯基五元杂环,导致来自β消除过程,具有较小的R基团(R = Me, CH = CH2)。该反应可用于甲醇中的原位脱甲硅烷基化反应和乙烯基双环[3.1.0]己烷的直接形成以及由1,7-烯炔形成一些烯基双环[4.1.0]庚烷。烯基双环 [3.1.0] 己烷的催化形成也发生在烯炔和 N2CHCO2Et 或 N2CHPh 中。该反应可以理解为通过 Ru=CHSiMe3
Enantioselective Rhodium-Catalyzed Cycloisomerization of (<i>E</i>
)-1,6-Enynes
An enantioselective rhodium(I)‐catalyzed cycloisomerization reaction of challenging (E)‐1,6‐enynes is reported. This novel process enables (E)‐1,6‐enynes with a wide range of functionalities, including nitrogen‐, oxygen‐, and carbon‐tethered (E)‐1,6‐enynes, to undergo cycloisomerization with excellent enantioselectivity, in a high‐yielding and operationally simple manner. Moreover, this RhI‐diphosphane
据报道,具有挑战性的(E)-1,6-烯炔的对映体选择性的铑(I)催化的环异构化反应。这种新颖的工艺使具有多种功能的(E)-1,6-炔烃(包括氮,氧和碳束缚的(E)-1,6-炔烃)能够以优异的对映选择性进行环异构化。高收益且操作简单的方式。此外,这种Rh I-二膦催化体系还显示出对(Z)-1,6-烯炔的优异反应性和对映选择性。使用DFT研究概述了使用Rh I -BINAP和Rh I -TangPhos的(E)-和(Z)-1,6-炔烃之间显着的反应性差异的原理,并通过DFT研究概述了该现象,从而为设计新的催化剂系统和方法提供了必要的见识。用于合成的应用程序。
Catalytic Dicyanative 5-exo- and 6-endo-Cyclization Triggered by Cyanopalladation of Alkynes
作者:Shigeru Arai、Yuka Koike、Atsushi Nishida
DOI:10.1002/adsc.200900813
日期:2010.3.22
A stereoselective dicyanative 5‐exo‐ and 6‐endo‐cyclization using various enynes has been investigated. The mode of cyclization is critically controlled by the structure of the substrates. For example, N‐allyl derivatives prefer 5‐exo‐cyclization, while methacryloyl amides are transformed to the corresponding lactams with tetra‐substituted carbons at the alpha‐position via 6‐endo‐cyclization. Both
Pendant Alkenes Promote Cobalt−Cobalt Bond Cleavage in (Alkyne)(binap)tetracarbonyldicobalt(0) Complexes
作者:Susan E. Gibson、Karina A. C. Kaufmann、Peter R. Haycock、Andrew J. P. White、David J. Hardick、Matthew J. Tozer
DOI:10.1021/om070022v
日期:2007.3.1
Heating (alkyne)(binap)tetracarbonyldicobalt(0) complexes bearing pendant alkenes leads to cleavage of the cobalt−cobalt bond and generation of the mononuclear hydride (binap)(CO)2CoH at 45−55 °C.