Preparation of Solid Polyfunctional Alkynylzinc Pivalates with Enhanced Air and Moisture Stability for Organic Synthesis.

We report the preparation of solid and air-stable polyfunctionalized alkynylzinc pivalates from the corresponding alkynes using TMPZnOPiv (TMP=2,2,6,6-tetramethylpiperidyl) as base. These organozinc pivalates are obtained as powders under mild conditions in excellent yields and can be manipulated in air for several hours without significant decomposition. These zinc reagents show an excellent reactivity in various carbon-carbon bond- forming reactions and 1,3-dipolar cycloadditions. An alkynylzinc pivalate has been used to prepare a carboxyamidotriazole with potential antineoplastic activity in eight steps and 38 % overall yield.