Unidirectional thermal electrocyclic ring forming reactions of methylenecyclobutenes from vinylallenes in the retinoid series
作者:José García Rey、Jesús Rodríguez、Angel R. de Lera
DOI:10.1016/s0040-4039(00)73735-x
日期:1993.9
A unidirectional, regiospecific formation of methylenecyclobutenes from substituted divinylallenes related to the 11,7-retroretinoids has been found at temperatures considerably lower than the parent system. Kinetic data are reported for the examples studied and an ab initio study is presented which favors a non-planar twist structure for the diene subunit undergoing cyclization.
[EN] PROCESS FOR THE PRODUCTION OF 1,3,3-TRIMETHYL-2-(3-METHYLPENT-2-EN-4-YNYL)CYCLOHEX-1-ENE<br/>[FR] PROCÉDÉ DE PRODUCTION DE 1,3,3-TRIMÉTHYL-2-(3-MÉTHYLPENT-2-ÉN-4-YNYL)- CYCLOHEX-1-ÈNE
申请人:DSM IP ASSETS BV
公开号:WO2012175396A1
公开(公告)日:2012-12-27
The present invention relates to an improved process for the production of 1,3,3-trimethyl-2-(3-methylpent-2-en-4-ynyl)cyclohex-1-ene, highly enriched in the Z-isomer, and the use of such compounds in organic syntheses, especially in processes forming intermediates (building blocks) the synthesis of vitamin A or β-carotene or other carotenoids, e.g. canthaxanthin, astaxanthin or zeaxanthin.