Alkynylhalocarbenes 3. * Synthesis of 2-(alk-1-ynyl)oxiranes from 1,1-dichloroalk-2-ynes and 3-substituted 3-bromo-1,1,1-trichloropropanes under the action of potassium tert-butoxide in the presence of alkali metal alkoxides

Article abstract of DOI:10.1007/bf02503489

(Alk-1-ynyl)chlorocarbenes (3), generated from 1,1-dihaloalk-2-ynes and 3-substituted 3-bromo-1,1,1-trichloropropanes under the action of Bu^tOK in THF at 20 °C, react with excess alkali metal alkoxide 4 to give 3-substituted 2-(alk-1-ynyl)oxiranes (6) in 26-78% yields, most likely as a result of insertion of carbene 3 into the α-C-H bond of alkoxides 4 and subsequent cyclization of the resulting 1-substituted 2-chloro-2-(alk-1-ynyl)etoxides. The yields of oxiranes 6 depend on the nature of the alkali metal used to prepare alkoxides 4 and on the method employed for the preparation of the latter.