Diamine-Free Lithiation−Trapping of <i>N</i>-Boc Heterocycles using <i>s</i>-BuLi in THF
作者:Graeme Barker、Peter O’Brien、Kevin R. Campos
DOI:10.1021/ol1017799
日期:2010.9.17
A diamine-free protocol for the s-BuLi-mediated lithiation-trapping of N-Boc heterocycles has been developed. In the optimized procedure, lithiation is accomplished using s-BuLi in THF at 30 degrees C for only 5 or 10 min. Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered a range of functionalized pyrrolidines, imidazolidines, and piperazines in 43-83% yield.
Direct β-Alkylation of Secondary Alcohols with Primary Alcohols Catalyzed by a Cp*Ir Complex
A new catalytic system for beta-alkylation of secondary alcohols has been developed. In the presence of [Cp*IrCl2](2) (CP* = pentamethylcyclopentadienyl) catalyst and base, the reactions of various secondary alcohols with primary alcohols give beta-alkylated higher alcohols in good to excellent yields without any hydrogen acceptor or hydrogen donor. This reaction proceeds via successive hydrogen-transfer reactions and aldol condensation.