The Chemistry of Borylstannanes: Oxidative Addition to Palladium Species and Its Application to Palladium-Catalyzed Borylstannation of Alkynes

Abstract

cis addition of the borylstannanes Me3SnB[NMe(CH2CH2)NMe] (1) and Me3SnB(NEt2)2 (4) across alkynes was efficiently catalyzed at room temperature or 80 °C by Pd(PPh3)4, Pd(dba)2, Cl2Pd(PPh3)2, or Me2Pd[PMe2(CH2CH2)PMe2] to give (β-stannylalkenyl)boranes in high yields. Treatments of 1 with Me2Pd[PMe2(CH2CH2)PMe2] and of 4 with cis-Me2Pd(PPh2Me)2 gave [{MeN(CH2CH2)MeN}B](Me3Sn)Pd[PMe2(CH2CH2)PMe2] (5) and [(Et2N)2B](Me3Sn)Pd(PPh2Me)2 (6), respectively, with the former characterized by X-ray analysis. Complex 5, when treated with 1-octyne, formed the corresponding (β-stannyl-1-octen-1-yl)borane and could catalyze the addition reaction of 1 with 1-octyne.