Rhodium(I)-CataIyzed 1,4-Silicon Shift of Unactivated Silanes from Aryl to Alkyl: Enantioseleetive Synthesis of Indanol Derivatives

摘要

In the search for atom-economic and sustainable transformations, the selective functionalization of unactivated C—H bonds is a major topic of organometallic chemistry.A specific class of such activations are 1,4-hydrogen-metal shifts which are mostly observed with organorhodium and -palladium species. One major driving force for these shifts is a stabilization of the system by the formation of a stronger carbon-metal bond. Therefore, mostly migrations from C_(alkyl)-(sp~3)-M or C_(vinyl)(sp~2)-M to C_(aryl)(sp~2)-H are observed.This reactivity trend can be exploited to relay organometallic species. While such tactic often leads to versatile aryl metal species, the originating position of the metal remains unfunc-tionalized. From a practical point of view, methods that would allow for a positional switch of two reactive functional groups are desirable. Therefore we investigated reactions involving the transfer of a synthetically versatile silyl group instead of a hydrogen atom, thus representing overall a silicon/metal swap [Eq. (1)] To the best of our knowledge such a concept has not yet been explored.