ALKYNYLHALOCARBENES. 2. GENERATION OF (ALKYN-1-YL)CHLOROCARBENES BY BASIC SOLVOLYSIS OF 1,1-DICHLORO-2-ALKYNES AND THEIR REACTION WITH OLEFINS: SYNTHESIS OF 1-CHLORO-1-ALKYNYLCYCLOPROPANES

Article abstract of DOI:10.1007/BF00864534

1,1-Dichloro-2-alkynes R¹C<*>CCHCl2 (4a-g: R¹=Me, n-Pr, c-Pr, t-Bu, Ad, Nor, Ph) were synthesized with yields of 50-75percent by chlorination with PCl5 of formylacetylenes (3a-g), prepared by oxidation of propargyl alcohols (1a-d) with CrO3*Py*HCl complex or acidolysis of propargyl acetals (2a-c) in the presence of catalytic quantities of pyridine; the corresponding alkynylchlorocarbenes, R¹C<*>CCCl (5a-g) were generated from them with powdered KOH in a two-phase system or t-BuOK. The latter were trapped by olefins with formation of 1-chloro-1-alkynylcyclopropanes (6a-t) with yields of up to 90percent.Keywords: alkynylchlorocarbenes, 1,1-dichloro-2-alkynes, basic solvolysis, interphase catalysis, 1-chloro-1-alkynylcyclopropanes.