Highly reactive metals from potassium—graphite. Preparation and use of titanium—graphite and tin—graphite
作者:Gian Paolo Boldrini、Diego Savoia、Emilio Tagliavini、Claudio Trombini、Achille Umani-Ronchi
DOI:10.1016/0022-328x(85)88107-9
日期:1985.2
The potassium—graphite route to active forms of metals has been extended to the preparation of titanium—graphite (TiGr) and tin—graphite (SnGr). The TiGr is used to achieve the reductive coupling of ketones to give alkenes, and SnGr is used in the preparation of diallyltin dibromide complexes which react with aldehydes to give homoallylic alcohols.
Barbier-type allylation of carbonyl compounds and imines with metallic cadmium
作者:Bir Sain、Dipak Prajapati、Jagir S Sandhu
DOI:10.1016/s0040-4039(00)61288-1
日期:1992.8
Cadmium mediated allylation of a variety of carbonylcompounds and imines in a Cd/Bu4NBr/THF system afforded excellent yields of the corresponding homoallylic alcohols and amines under very mild reaction conditions.
在Cd / Bu 4 NBr / THF系统中,镉介导的各种羰基化合物和亚胺的烯丙基化在非常温和的反应条件下提供了极佳的相应均烯丙基醇和胺收率。
Allylic sulfones as allyl anion equivalents: homoallylic alcohols from metal catalysed reactions of sulfones with aldehydes and ketones
作者:Jonathan Clayden、Marc Julia
DOI:10.1039/c39940001905
日期:——
Reduction of allylic sulfones with diethylzinc, catalysed by palladium(0), gives nucleophilic organometallic species, which react in situ with carbonyl compounds to give homoallylic alcohols in high yield.
to produce unisolable allylchromium species which add efficiently to aldehydes or ketones with high degree of stereo- and chemoselectivity. Particularly, high threo selectivity is observed in the reaction of aldehydes and 1-bromo-2-butene and is ascribed to a chair-like six-membered transition state. Simple reduction of allylic and benzylic halides produces biallyls and bibenzyls, while gem-dibromocyclopropanes
organozinc derivatives to Iron stabilized TMM-alcohols. These are decomplexed, under partial hydrogenation, by photolysis in acetic acid to give allylic and homoallylic isoprenoic alcohols. Starting from the optically active complex (+)-3, this allows a rapid synthesis of (R)-(-)-Ipsdienol of high ee.