Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes. Part 15: Regioselectivity of the opening reactions with MeOH of remote O-substituted regio- and diastereoisomeric pyranosidic epoxides under condensed- and gas-phase operating conditions
作者:Paolo Crotti、Gabriele Renzi、Lucilla Favero、Graziella Roselli、Valeria Di Bussolo、Micaela Caselli
DOI:10.1016/s0040-4020(03)00078-4
日期:2003.2
The regiochemical behavior of pairs of regio- and diastereoisomeric epoxides derived from the 3,4,5,6-tetrahydro-2H-pyrane system, bearing an acetal group as the remote functionality, was determined in the acid methanolysis in the condensed phase (cd-phase) and in the reaction with MeOH in the gas-phase using a gaseous acid (D3+), as the promoting agent. With only one exception, the results obtained
在缩合相的酸性甲醇分解中,确定了由3,4,5,6-四氢-2 H-吡喃体系衍生的成对的对-对映体和非对映异构体环氧化物的对区域化学行为(以缩醛为远程官能团)( cd-相)和在气相中与MeOH的反应中,使用气态酸(D 3 +)作为促进剂。仅有一个例外,在这些环氧化物的打开过程中获得的结果表明,D +介导的螯合双齿物种在气相中的侵入能够改变在cd相甲醇解中发现的区域化学结果。