Heterosubstituted cyclopropanation of alkenes with organochromium reagents derived from heterosubstituted dihalomethanes,CrCl2, and tetraalkylethylenediamine

Iodocyclopropanes of trans configuration are produced stereoselectively from terminal alkenes by treatment with a reagent derived from iodoform, chromium(II) chloride, and TEEDA (N,N,N′,N′-tetraethylethylenediamine) in THF. Similarly, cyclopropylsilanes and cyclopropylboronic esters are obtained by using R₃SiCHI₂, and a combination of Cl₂CHB(OR)₂ and LiI instead of iodoform, respectively. The heterocyclopropanation occurs selectively at terminal double bonds, and di- and trisubstituted double bonds in the same molecules remain unchanged. Such functional groups as alcohol, ether, silyl ether, ester, tertiary amine, and amide groups are compatible with the reaction conditions.