Typical procedure for the preparation of 2: Bu 3 SnMgMe was obtained at −20°C by addition of MeMgI (78 mmol, 3.2 M in ether) to Bu 3 SnLi (78 mmol, in 40 ml THF) previously prepared by deprotonation of Bu 3 SnH with iPr 2 NLi. At −20°C, the Bu 3 SnMgMe solution was subsequently stirred with CuCN (5% mol) before dropwise addition of alkyne (0.4 eq) and quenching with methyl iodide (2.3 eq). After usual workup, vinyltin 2 was isolated by distillation (Eb 0.06 = 114°C).
