Collect. Czech. Chem. Commun.
1982, 47, 3062-3076
https://doi.org/10.1135/cccc19823062
Neighboring group participation in hypobromous acid addition to 19-substituted 5α-cholest-1-enes and in acid cleavage of their epoxy analogs
Václav Černý and Pavel Kočovský
Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6
Abstract
Reactions of the title compounds (bearing an OH, OCH3 or OCOCH3 group at C(19)) involve 5(O)n, 7(O)π,n-participation by the 19-substituent or attack by an external nucleophile. The 6(O)π,n-participation does not occur. The behavior of 1,2-unsaturated (or epoxidated) compounds has been compared with the earlier described 2,3-unsaturated or epoxidated analogs. The 1,2-type is genarally less prone to participation. The reasons for this behavior are discussed.
