A copper-catalyzed asymmetric reductive allyl–allyl cross-coupling reaction of allenes with allylic phosphates wherein allenes were used as allylmetal surrogates has been achieved for the first time. This protocol provides an efficient and straightforward route to optically active 1,5-dienes in a highly enantioselective and site-specific fashion. Furthermore, all-carbon quaternary stereogenic centers
Ligand Controlled Highly Selective Copper-Catalyzed Borylcuprations of Allenes with Bis(pinacolato)diboron
作者:Weiming Yuan、Shengming Ma
DOI:10.1002/adsc.201100929
日期:2012.7.9
Copper‐catalyzed highlyselectiveborylcuprations of allenes with bis(pinacolato)diboron produce two different types of alkenylboranes by applying a ligand effect. In the presence of tris(para‐methoxyphenyl)phosphine [P(C6H4OMe‐p)3], the reaction of aryl‐1,2‐dienes affords 2‐alken‐2‐yl boronates as the only product with exclusive Z‐geometry; the regioselectivity is switched to afford the 1‐alken‐2‐yl
铜催化的具有双(频哪醇)二硼烷的丙二烯的高选择性硼烷基cup通过施加配体效应产生两种不同类型的烯基硼烷。在存在三(对-甲氧基苯基)膦[P(C 6 H 4 OMe- p)3 ]的情况下,芳基1,2-二烯的反应提供2-烯丙基-2-基硼酸酯作为唯一的独家产品Z几何 当使用二齿膦2,2'-双(二苯基膦基)联苯作为配体时,区域选择性切换为主要产物1-烯丙基-2-基硼酸酯。
Substituent effects on rates of rhodium-catalyzed allene cyclopropanation
作者:Timothy M. Gregg、Russell F. Algera、John R. Frost、Furqan Hassan、Robert J. Stewart
DOI:10.1016/j.tetlet.2010.09.143
日期:2010.12
cyclopropanations. Relative reaction rates for aliphatic allenes were found to be similar to those for aryl-substituted allenes, but silicon substitution was found to give a 5- to 14-fold rate increase. The rate enhancement effect for 1-silyl allenes can partially make up for loss of rate and regioselectivity, with 1-trimethylsilyl-1,2-butadiene exhibiting high levels of enantioselectivity and diastereoselectivity
Conversion of Alkyl- and Arylallenes into 1-Alkynes Through Metallated Intermediates
作者:F. Taherirastgar、L. Brandsma
DOI:10.1080/00397919708005448
日期:1997.12
Abstract: A number of acetylenes RCH2C=CH have been obtained by metallation of the allenes RCH=C=CH2 or mixtures of acetylenes and allenes with n-BuLi in THF-hexane and hydrolysis after allowing the metallated allenes to rearrange at room temperature or by heating under reflux.
The formation of pentafluorophenyl indenes upon reaction of arylallenes with B(C6F5)3 is reported. Key steps are a 1,1-carboboration and a retrohydroboration.