Synthesis and Reactivity of a Zinc Diazoalkyl Complex: [3+2] Cycloaddition Reaction with Carbon Monoxide

Abstract This work reports the synthesis, characterization, and reactivity of the first example of a well‐defined zinc α‐diazoalkyl complex. Treatment of zinc(I)‐zinc(I) bonded compound L 2 Zn 2 [ L =CH 3 C(2,6‐ i Pr 2 C 6 H 3 N)CHC(CH 3 )(NCH 2 CH 2 PPh 2 )] or zinc(II) hydride L ZnH with trimethylsilyldiazomethane affords zinc diazoalkyl complex L ZnC(N 2 )SiMe 3 . This complex liberates N 2 in the presence of a nickel catalyst to form an α‐zincated phosphorus ylide by reacting with the pendant phosphine. It selectively undergoes formal [3+2] cycloaddition with CO 2 or CO to form the corresponding product with a five‐membered heterocyclic core. Notably, the use of CO in such a [3+2] cycloaddition reaction is unprecedented, reflecting a novel CO reaction mode.