作者:Louis Barriault、Jermaine D. O. Thomas、Roxanne Clément
DOI:10.1021/jo020664m
日期:2003.3.1
The successful stereocontrol of the Diels-Alderreaction of semicyclicdienes possessing a secondary and tertiary allylic magnesium alkoxide alcohol functionality and activated dienophiles such as methyl acrylate, methacrolein, acrolein, and N-phenylmaleimide is described.
Enantioselective Diels−Alder Cycloadditions with (S<i>S</i>)-2-(<i>p-</i>Tolylsulfinyl)-1,4-naphthoquinone: Efficient Kinetic Resolution of Chiral Racemic Vinylcyclohexenes
作者:M. Carmen Carreño、Antonio Urbano、Claudio Di Vitta
DOI:10.1021/jo9811874
日期:1998.11.1
Chiral racemic vinylcyclohexenes 1a-m, bearing allylic and nonallylic oxygenated substituents on the cyclohexene ring, were submitted to Diels-Alder reactions with enantiomerically pure (SS)(2-p-tolylsulfinyl)-1,4-naphthoquinone. The tandem cycloaddition/pyrolytic sulfoxide elimination led to the formation of enantiomerically enriched angularly tetracyclic quinones (+)-8a and (+)-12, arising from the kinetic resolution of the racemic diene. Dienes la-c, bearing an alkoxy substituent at the allylic position C-3, and 1d-g, with C-3 alkoxy and C-5 methyl groups, gave exclusively quinones (+)-8a-g, resulting from the anti approach to the dienophile. A similar anti selectivity occurred in cycloadditions of dienes 1ij, viith the alkoxy group situated at the allylic position C-6. Nonallylic 4-substituted vinylcyclohexenes 1k-m evolved to ca. 75:25 mixtures of (+)-anti-8k-m and (+)-syn-12k-m derivatives. In all cases, (SS)-(2-p-tolylsulfinyl)-1,4-naphthoquinone reacted from the less hindered face of the more reactive s-cis conformation, giving rise to products in moderate to excellent enantiomeric excesses. Steric effects and torsional interactions in the corresponding approaches account for the observed pi-facial diastereoselectivities at both partners.
Photooxygenation of 1-vinylcycloalkenes. The competition between ene reaction and cycloaddition of singlet oxygen
作者:Werner Herz、Rouh Rong Juo
DOI:10.1021/jo00205a013
日期:1985.3
Palladium(0) catalyzed reaction of 1,3-diene epoxides. A useful method for the site-specific oxygenation of 1,3-dienes
作者:M. Suzuki、Y. Oda、R. Noyori
DOI:10.1021/ja00500a058
日期:1979.3
An Efficient Stereoselective Synthesis of Z-2-(2-Methylene Cyclohexylidene)ethanol by the Photosensitized Oxygenation of 1-Vinylcyclohexene. A Model for Ring A of Calcitriol