Reagent for the Formation of Borylcyclopropanes

　2-(Diiodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1) is a reagent for the synthesis of multisubstituted cyclopropane rings. Charette’s group reported the generation of carbenoids from 1 with ethylzinc trifluoroacetate and further transformation through the Simmons-Smith reaction.¹⁾ In addition, Takai et al. reported the borylcyclopropanation of unactivated alkenes with 1 in the presence of chromium(II) chloride and TMEDA.²⁾ The obtained borylcyclopropanes can be further functionalized from the boronic ester moiety.