3‐butadienes with various substitution patterns were formed in good to high yields in a copper‐catalyzed borylation of α‐alkoxy allenes with bis(pinacolato)diboron (see scheme; Bn=benzyl, pin=pinacolate, L is an N‐heterocyclic carbene ligand). The products were found to be useful intermediates for the synthesis of cyclic vinyl boranes, α,β‐unsaturated ketones, and functionalized multisubstituted dienes.
Synthesis of 2-Substituted 2-Amino Ketones by Rhodium-Catalyzed Reaction of<i>N</i>-Sulfonyl-1,2,3-triazoles with 2-Alkenols
作者:Tomoya Miura、Takamasa Tanaka、Qiang Zhao、Scott G. Stewart、Masahiro Murakami
DOI:10.1002/hlca.201600320
日期:2017.2
A study on a rhodium(II)‐catalyzed reaction of N‐sulfonyl‐1,2,3‐triazoles with 2‐alkenols is reported. The reaction is initiated by insertion of an α‐imino carbene into the O–H linkage of alcohol, forming a 2‐alkenoxy enamide intermediate. A thermal [3,3]‐sigmatropicrearrangement follows to yield 2‐substituted 2‐amino ketone in a stereoselective manner. The successful application of this methodology
Carbometalation–Carboxylation of 2,3-Allenols with Carbon Dioxide: A Dramatic Effect of Halide Anion
作者:Suhua Li、Bukeyan Miao、Weiming Yuan、Shengming Ma
DOI:10.1021/ol4000197
日期:2013.3.1
and stereoselective carbomagnesiation of 2,3-allenols with Grignard reagents may smoothly react with carbon dioxide to afford 2(5H)-furanones. A dramatic effect of the halide anion from the Grignard reagent (Br vs Cl) for CO2 activation was observed. The reaction proceeded smoothly under mild conditions to afford the products in 58–93% yields.
用格氏试剂通过CuCl介导的2,3-烯醇的高度区域选择性和立体选择性碳还原反应形成的环状有机金属中间体可与二氧化碳平稳反应,得到2(5 H)呋喃酮。观察到了来自格氏试剂的卤化物阴离子(Br vs Cl)对CO 2活化的显著作用。反应在温和的条件下平稳进行,以58-93%的收率得到产物。
An Efficient CuCN-Catalyzed Synthesis of Optically Active 2,3-Allenols from Optically Active 1-Substituted 4-Chloro-2-butyn-1-ols
作者:Jing Li、Wangqing Kong、Chunling Fu、Shengming Ma
DOI:10.1021/jo900710e
日期:2009.7.17
The sequential treatment of opticallyactive terminal propargylic alcohols with n-BuLi/(HCHO)n and regioselective chlorination afforded the corresponding opticallyactive 4-chloro-2-butyn-1-ols. With R1 being a methyl or an ethyl group, an alternative for the synthesis of the corresponding opticallyactive propargylic alcohols is the Novozym 435-catalyzed kinetic resolution of these racemic 4-chloro-2-butyn-1-ols
Highly Regio- and Stereoselective Copper(I) Chloride-Mediated Carbometallation of 2,3-Allenols with Grignard Reagents
作者:Zhan Lu、Shengming Ma
DOI:10.1002/adsc.200600532
日期:2007.5.7
An efficient highly regio- and stereoselective copper(I) chloride-mediated carbometallation of differently substituted 2,3-allenols with primary or secondary alkyl or aromatic Grignardreagents followed by iodination to synthesize fully-substituted allylic alcohols has been developed. This protocol introduces the R4 group from the Grignardreagent to the terminal position of the 2,3-allenols.