Regioselective and stereoselective syntheses of 1,2,3-triaminocyclohexane derivatives
摘要:
The reactions of trans- and cis-3-bromo-1,2-epoxycyclohexanes with pyrrolidine are described. While in the case of the trans-epoxide 2 the diamino alcohol 3 was obtained in benzene, the cis-epoxide 5 unexpectedly led to bromo amino alcohol 7 in benzene. Compound 7 could be converted to 3 using pyrrolidine in DMF. The trans-3-chloro-1,2-epoxycyclohexane 11 was the source of the isomeric diamino alcohol 4. The diamino alcohols 3 and 4 were used to produce triamines containing two pyrrolidine and one methylamine residues (14, 15, 22). The bromo amino alcohol 7 was used to prepare a triamine containing two methylamine and one pyrrolidine residues (25). The triamines were converted to amide derivatives. The structure of one of these amides (23) was confirmed by single crystal X-ray analysis.
Diastereoselectivity in the Epoxidation of Substituted Cyclohexenes by Dimethyldioxirane1,2
摘要:
Three series of compounds based on the cyclohexene framework. have been epoxidized by dimethyldioxirane. A pronounced dependence of epoxide diastereoselectivity on substituent has been observed. In addition there is a solvent influence on this stereoselectivity. The results have been explained by invoking steric, H-bonding, and dipole-dipole influences on the epoxide stereochemistry.
Radical reactions of epoxides. Chlorine-atom abstraction from .alpha.- and .beta.-chloro epoxides by the triphenyltin radical
作者:Kevin W. Krosley、Gerald Jay Gleicher、Gary E. Clapp
DOI:10.1021/jo00029a011
日期:1992.1
The four isomers of chloroepoxypropane have been prepared, and their relative reactivities with triphenyltin hydride have been determined. The three alpha-chloroepoxypropanes react at a much slower rate than does epichlorohydrin, the only beta-chloro epoxide of the four. The nature of the increased reactivity for the beta-chloro epoxides has been investigated by studying two pair of diastereomeric beta-chloro epoxides, and a single acyclic beta-chloro ether. The results are discussed in terms of the inductive, resonance, and stereoelectronic effects of the epoxide.