Two methods for the preparation of 2-cyclohexenones from resin-bound 1,3-cyclohexanedione
作者:Mark E. Fraley、Robert S. Rubino
DOI:10.1016/s0040-4039(97)00631-x
日期:1997.5
The addition of organolithium or Grignard reagents to vinylogous ester resin 1 followed by mild hydrolysis of product resins 2 provides 3-alkyl-2-cyclohexenones in high purity (>95%). Alternatively, conversion of 1 to vinyl triflate resin 4 followed by palladium-mediated couplings with aryl boronic acids and hydrolysis furnishes 3-aryl-2-cyclohexenones in lower yield, but exceptional purity.
A Fe2(CO)9-mediated [5+1] cycloaddition of vinylcyclopropanes (VCPs) and CO to α, β-cyclohexenones has been developed. The reaction can tolerate aryl and aliphatic groups at the α-position of VCPs, while VCP substrates with vinyl or alkynyl substitutions are not suitable ones. In addition, this reaction can also be used to synthesize bicyclic rings if an aryl group is attached to the vinyl moiety of
Aerobic Oxidative Heck/Dehydrogenation Reactions of Cyclohexenones: Efficient Access to<i>meta</i>-Substituted Phenols
作者:Yusuke Izawa、Changwu Zheng、Shannon S. Stahl
DOI:10.1002/anie.201209457
日期:2013.3.25
catalyst, employing a 6,6′‐dimethyl‐2,2′‐bipyridine ligand, promotes both the aerobic oxidative Heck coupling and dehydrogenation reactions of cyclohexenones. These reactions may be combined in a one‐pot sequence to enable the straightforward synthesis of meta‐substituted phenols (see scheme).
One-pot synthesis of Robinson annulated 3-aryl-cyclohexenones from allyl alcohols and ketones using palladium is reported. Long chain aliphatic or aryl substitutions at the C1 position of allyl alcohol result in the formation of 1,5-diketone products. This simple one-pot method avoids the use of highly electrophilic vinyl ketones.