An enantioselective oxidative carbocyclization–borylation of enallenes that is catalyzed by palladium(II) and a Brønsted acid was developed. Biphenol‐type chiral phosphoric acids were superior co‐catalysts for inducing the enantioselective cyclization. A number of chiral borylated carbocycles were synthesized in high enantiomeric excess.
Reactions of Grignard reagents from 1-halogenoallenes. Allenes—XXXIII
作者:P.M. Greaves、S.R. Landor、M.M. Lwanga
DOI:10.1016/0040-4020(75)80150-5
日期:1975.1
Grignardreagents have been prepared from 1-bromo-3,3-dialkylallenes in ether or tetrahydrofuran. The allenic acids, 4,4-dialkylbuta-2,3-dienoic acids together with 4,4-dialkylbut-2-ynoic acids are formed with carbon dioxide to the exclusion of acids with a terminal acetylene group. Two coupled products, 3,4-diethyl-3,4-dimethylhexa-1,5-diyne and 3-ethyl-3,6-dimethylocta-4,5-dien-1-yne, which are formed
Convenient method for the stereoselective synthesis of 3-phenyl-1-alkynes
作者:Anna Maria Caporusso、Carmela Polizzi、Luciano Lardicci
DOI:10.1021/jo00226a038
日期:1987.8
Study on halolactamization-γ-hydroxylation or haloiminolactonization of 2,3-alkadienamides
作者:Shengming Ma、Hexin Xie
DOI:10.1016/j.tet.2004.10.050
日期:2005.1
The reactions of 4-mono- or 4-unsubstituted 2,3-alkadienamides with CuX2 afforded 5-hydroxypyrTol-2(5H)-ones via the sequential lactamization and gamma-hydroxylation process in aqueous THF while those of 4,4-disubstituted 2,3-alkadienamides with CuX2 in THF afforded iminolactones in high yields. Iodoiminolactonization and iodolactamization/gamma-hydroxylation were achieved by the corresponding reaction with I-2 in THF at rt. The structures of the products depend on the steric hindrance at the 4-position of the starting allenamides. Relatively electron-rich allenes afforded the corresponding products in much higher yields under milder reaction conditions implying the intramolecular electrophilic nature of the cyclization reaction. (C) 2004 Elsevier Ltd. All rights reserved.