First preparation of allyl vanadium reagents in a mixed solvent of THF and HMPA (HMPA = hexamethylphosphoric triamide) and their application to allylation of carbonyl compounds
作者:Yasutaka Kataoka、Isamu Makihira、Kazuhide Tani
DOI:10.1016/0040-4039(96)01579-1
日期:1996.9
Allylation of carbonylcompounds with allyl bromide mediated by a vanadium(II) complex in a mixedsolvent of THF and HMPA (HMPA = hexamethylphosphorictriamide) has been accomplished. Coordination of HMPA to a vanadium metal is essential for the stabilization of the allylvanadium species.
method for the highlydiastereoselective preparation of anti tertiary homoallylic alcohols has been developed. The reaction of allyltitanocenes, generated by the reductive titanation of various allylic substrates with a titanocene(II) species, with a variety of ketones produced the anti tertiary homoallylic alcohols in good diastereoselectivity, even when using sterically less congested ketones (see scheme;