The fluoride promoted addition of allyltrimethylsilane to aldehydes (Hosomi-Sakurai reaction) was first reported in 1978 and has found extensive synthetic applications.1 While catalytic quantities of fluoride are sufficient for these reactions it has been recognized that fluoride acts as reaction initiator rather than as a catalyst with an alkoxide (X = O) autocatalytic cycle participating as shown below. As it would be beneficial to remove the requirement of toxic fluoride, a new approach has been developed in which trimethylsilanolate (TMSO-) can replace the role of fluoride. Under these conditions addition reactions can be achieved, at room temperature, for aldehydes, ketones and imines with benzyl, allyl, heteroaryl and 1,3-dithianyl substituted trimethylsilanes. Addition to chiral imines can also be achieved with excellent diastereoselectivity. Access to substituted benzylsilane starting reagents can be readily achieved via LiNK metalation of toluenes and TMSCl electrophile reaction.2 The nature of the trimethylsilane Lewis base activation with trimethylsilanolate will be illustrated.1. Hosomi, A.; Shirahata, A.; Sakurai, H. Tetrahedron Lett. 1978, 19, 3043.2. Fleming, P.; O'Shea, D.F. J. Am. Chem. Soc. 2011  , 133, 1698.

Lewis base mediated (fluoride free) addition reactions of trimethylsilanes

245th National Meeting (2013)

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