Rhenium-catalyzed [2+2] Cycloadditions of Norbornenes with Internal and Terminal Acetylenes
作者:Yoichiro Kuninobu、Peng Yu、Kazuhiko Takai
DOI:10.1246/cl.2007.1162
日期:2007.9.5
Treatment of norbornenes with internal and terminal acetylenes in the presence of a catalytic amount of [ReBr(CO)3(thf)]2 gave cyclobutene derivatives in good to excellent yields.
Ruthenium-Catalyzed [2 + 2] Cycloadditions between Bicyclic Alkenes and Alkynyl Halides
作者:Karine Villeneuve、Nicole Riddell、Robert W. Jordan、Gavin C. Tsui、William Tam
DOI:10.1021/ol048111g
日期:2004.11.1
Ru-catalyzed [2 + 2] cycloadditions between norbornadiene and alkynylhalides were found to occur in moderate to good yields (32-89%). The presence of the halide moiety greatly enhances the reactivity of the alkyne component in the cycloaddition and can be transformed into a variety of products that are difficult or impossible to obtain via direct cycloaddition. [reaction: see text]
1,2-bis(phenylsulfonyl)alkenes as versatile groups in organic synthesis: The preparation of alkyl- and aryl-substituted norbornadienes via the Diels-Alder cycloaddition - Grignard reaction - desulfonylation sequence
作者:Ugo Azzena、Sergio Cossu、Ottorino De Lucchi、Giovanni Melloni
DOI:10.1016/s0040-4039(00)99595-9
日期:——
A syntheticmethodology for the preparation of the formal Diels-Alder cycloadducts of alkyl- and aryl-substituted acetylenes which exemplifies the utility of bis(phenylsulfonyl)alkenes 1 in organic synthesis is presented. The procedure entails [4+2]-cycloaddition of (E)-1,2-bis(phenylsulfonyl)-1-chloroethylene (4), Grignard reaction and desulfonylation; each step occurs in high yield.