Tetrabutylammonium difluorotriphenylsilicate TBAT

A copper enolate is also regarded as an intermediate in a hetero-Diels-Alder-like sequence between a ketone and an analog of Danishefsky s diene, modified at silicon ii.e., (0Et)3 in place of Mes Scheme 1-12)J A fluoride-initiated (tetrabutylammonium difluorotriphenylsilicate [TBAT]) cleavage of the starting silyl enol ether leads to a nonracemically ligated (with Walphos) copper enolate, which condenses and then closes to the observed dihydropyranones in modest ee s. Noteworthy in this scheme is generation of the quaternary center. 

TMAF), tetrabutylammonium difluorotriphenylsilicate (TBAT) or the mixed salt 1 1 CsF-CsOH. Furthermore, the reaction can benefit from the use of ionic liquids as reaction media. Finally, a polymer-supported fluoride initiator has also been described, thus improving the ease of purification of the products. ... 

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