A ruthenium(<scp>ii</scp>)-catalyzed C–H allenylation-based approach to allenoic acids
作者:Xiaoyan Wu、Junjie Fan、Chunling Fu、Shengming Ma
DOI:10.1039/c9sc00603f
日期:——
A Ru(II)-catalyzeddirectaccess to various functionalized allenoic acids via C–Hallenylation of readily available aryl carboxylic acids with propargylic acetates is reported. Axially chiral allenoic acids could be obtained in high ee by using optically active propargylic acetates through a chirality transfer strategy.
Copper(I)-Catalyzed Substitution of Propargylic Carbonates with Diboron: Selective Synthesis of Multisubstituted Allenylboronates
作者:Hajime Ito、Yusuke Sasaki、Masaya Sawamura
DOI:10.1021/ja806602h
日期:2008.11.26
A versatile synthetic method for the preparation of the allenylboronates, Cu(I)-catalyzed reaction of propargylic carbonates with a diboron, is described. A Cu(O-t-Bu)-Xantphos catalyst system was effective for the preparation of various allenylboron compounds, allenylboronates with different substitution patterns, those with functional groups, and an axially chiral one. The Lewis acid promoted stereoselective addition to aldehydes leading to homopropargylic alcohols showed the usefulness of the new allenylboronates.
Palladium-catalyzed reduction of propargylic acetates with SmI2. A mild and convenient method for the preparation of allenes
A highly regioselective reduction of propargylic acetates has been attained by using SmI2 and catalytic Pd(0) in the presence of 2,4-dimethyl-3-pentanol affording various types of allenes in high yields.