Broad-Scope\n(3 + 2) Cycloaddition of Cyclopropanes\nand Alkynes Enabled by Boronyl Radical Catalysis

Cyclopentene skeletons are ubiquitous in natural products\nand small\nmolecule drugs. The (3 + 2) cycloaddition of cyclopropanes and alkynes\nrepresents an efficient and atom-economic strategy for synthesizing\nthese structures. However, the types of substituents on cyclopropane\nand alkyne used in previous works show evident limitations, restricting\nthe application of this type of reaction to some extent. Herein, we\nreport a broad-scope (3 + 2) cycloaddition of cyclopropanes and alkynes\ncatalyzed by boronyl radicals. In this method, various substrates,\nsuch as mono-, di-, tri-, and tetrasubstituted cyclopropanes, as well\nas mono- and disubstituted alkynes, were compatible with up to 98%\nisolated yield.