1,3-Migration of chloride and azide ligands in reactions of highly sterically hindered organosilicon halides

Abstract

Reaction of (Me₃Si)₂C(SiEt₂Cl)(SiMe₂1), 1, with AgBF₄ in CH₂Cl₂ or Et₂O gives a ca. 3:1 mixture of the unrearranged fluoride (Me₃Si)₂C(SiEt₂Cl)(SiMe₂F), 2, and the rearranged (Me₃Si)₂C(SiEt₂F)(SiMe₂Cl), 3. The reverse 1,3-migration of Cl takes place when (Me₃Si)₂C(SiMe₂Cl)(SiEt₂I), 4. is treated similarly in CH₂CI₂, a ca. 2:1 mixture of 2 and 3 being formed. Reaction of (Me₃Si)₂C(SiEt₂N₃)(SiMe₂Br), 5, with AgBF₄ in CH₂Cl₂ likewise gives a ca. 3:1 mixture of (Me₃Si)₂C(SiEt₂N₃)(SiMe₂F) and (Me₃Si)₂C(SiEt₂F)(SiMe₂N₃). The preparation of compounds 1, 4 and 5 and of the following (R = SiMe₃) are described: R₂C(SiMe₂Cl)(SiEt₂H), R₂C(SiEt₂Cl)(SiMe₂H) and R₂C(SiEt₂N₃)(SiMe₂H).