A catalytic asymmetric method for the synthesis of γ-substituted ketones via hydrogen borrowing alkylation of both racemic linear precursors and 1,5-diols is described. The base mediated racemization of an intermediate cyclohexenone facilities a dynamic kinetic resolution, affording highly enantioenriched cyclohexanes in excellent yields, which could be further functionalized by removal of the Ph* group. DFT modelling revealed the mode of enantioinduction to be a stepwise process comprising of a hydride transfer and a coordination change to a π-allylic enolate complex with the iridium catalyst.
Keywords:
dynamic kinetic resolution
,cyclohexanes
,hydrogen borrowing
,iridium
,asymmetric synthesis
