Enantiocontrolled Synthesis of Polychlorinated Hydrocarbon Motifs: A Nucleophilic Multiple Chlorination Process Revisited
摘要:
Polychlorinated hydrocarbon motifs have been synthesized in enantiomerically pure forms by means of nucleophilic multiple chlorinations of chiral epoxides, which stereospecifically incorporate halogen atoms into oxygenated molecular scaffolds. The present study demonstrates the scope of the N-chlorosuccinimide (NCS)/organophosphine reagent system that forms multiple sp(3)C-Cl bonds in a regularly repeating pattern, with proper stereochemical configurations and evaluates its applicability to various epoxides having elaborate structures. It is noteworthy that tetrachlorinated motifs are produced in one step from bisepoxides by using NCS/Ph3P. Furthermore, Ph2PCl used in combination with NCS has been found to serve as a potentially useful alternative to NCS/Ph3P, especially for promoting dichlorination reactions of alkenyl-substituted epoxides.
Convenient in situ generation of various dichlorinating agents from oxone and chloride: diastereoselective dichlorination of allylic and homoallylic alcohol derivatives
作者:Jingyun Ren、Rongbiao Tong
DOI:10.1039/c3ob40670a
日期:——
A safe and convenient protocol was developed for in situ generation of various dichlorinating agents (cf. Cl2, NCl3, Et4NCl3, ArICl2) from oxone and chloride. The synthetic utility of this protocol was demonstrated by diastereoselective dichlorination of a series of allylic and homoallylicalcohol derivatives with excellent yields and diastereoselectivity.