α-Cyclopropyl-α-trialkylsilyl alkoxides were formed either by addition of cyclopropyllithiums to acylsilanes or by addition of organolithiums to a cyclopropylformylsilane.[1, 2]-Brook rearrangement led to α-silyloxy organolithiums which on warming underwent cyclopropane ring opening and [1, 5]-retro-Brook rearrangement to yield γ-silyl ketones. Despite the favourability of the cyclopropane ring opening, the Brook rearrangement still required the ...