A convergent synthesis of symmetrical carotenoids using the Heck reaction
作者:Hugues Bienaymé
DOI:10.1016/0040-4039(94)85026-7
日期:1994.9
Regioselective Heck-type vinylation of various allylic alcohols with 2, followed by an acidic dehydration, delivers symmetricalcarotenoids in good yields. symmetricalcarotenoids.
4-(2,5-Dihydroxyphen-1-yl)-crotonic acid and its derivatives, and the
申请人:BASF Aktiengesellschaft
公开号:US04353836A1
公开(公告)日:1982-10-12
4-(2,5-Dihydroxyphen-1-yl)-crotonic acid and its derivative (I) ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each H or C.sub.1 -C.sub.8 -alkyl, R.sup.5 is H, C.sub.1 -C.sub.30 -alkyl or C.sub.2 -C.sub.30 -alkenyl, and R' is H or an organic radical which can be split off hydrogenolytically, and a process for the preparation of the compounds I, wherein a hydroquinone II ##STR2## is reacted, in the presence of from 0.1 to 2 moles of a Lewis acid per mole of II, with (a) a vinylglycolic acid derivative IIIa ##STR3## or (b) a crotonic acid derivative IIIb ##STR4## where X is halogen, hydroxyl or C.sub.1 -C.sub.4 -alkoxy or acyloxy.