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.
this study, in situ catalytically generated allylic indium from 1,3 dienes and InCl2H was developed for use in the allylation of ketones. This protocol resulted in the unprecedented establishment of a successive combining of quaternary C–C bonds, which could then be applied to many types of ketones. Other branched 1,3 dienes and vinyl cyclopropanes, could also be coupled with ketones in a reaction where
A case of highly diastereoselective addition to unsymmetrical ketones:lk-addition of (2-alkenyl)triphenoxytitanium derivatives
作者:Dieter Seebach、Leo Widler
DOI:10.1002/hlca.19820650704
日期:1982.11.3
(2-Butenyl)-, (4-methyl-2-pentenyl)-, and (2-heptenyl)triphenoxytitanium (2a–c) add to dialkyl, alkyl aryl-, and alkinyl aryl ketones to give high yields of tertiary homoallylic alcohols (5–12), which are diastereomerically enriched up to 98%. Configurational assignment by degradation of two of the products to olefins 15 and 18 - through β-hydroxy acids 13 and 16 and β-lactones 14 and 17 - leads to