[reaction: see text] This Mg-TiCl4-promoted CH2-transfer reaction of CH2Cl2 represents an extremely simple, practical, and efficient methylenation of a variety of ketones and aldehydes, especially in enolizable or sterically hindered ketones such as 2,2-dimethylcyclohexanone, camphor, and fenchone.
Total Synthesis of the Cytotoxic Guaipyridine Sesquiterpene Alkaloid (+)-Cananodine
作者:Donald Craig、Gavin D. Henry
DOI:10.1002/ejoc.200600414
日期:2006.8
The enantiospecific total synthesis of the cytotoxic guaipyridine sesquiterpene alkaloid (+)-cananodine (1) is described. A chiral pool/chiral auxiliary basedapproach is described for the synthesis of a key oxazolidinone intermediate. Subsequent key steps involve diastereoselective oxazolidinone allylation, cycloheptenylmethanol formation using ring-closing olefin metathesis, microwave-assisted decarboxylative
Remote participation during photooxidation at sulfur. Evidence for sulfurane intermediates
作者:E. L. Clennan、Kang Yang
DOI:10.1021/jo00042a031
日期:1992.7
The photooxidations of geminally substituted gamma-hydroxy sulfides results in formation of unusual oxidative elimination products. Detailed spectral data and the independent synthesis of a close analogue provide compelling evidence for the structures of these olefins. The formation of the olefins is attributed to decomposition of sulfurane intermediates. This conclusion is supported by a detailed kinetic study which separated the chemical, k(r), and physical, k(q), components to the overall deactivation of singlet oxygen. Those sulfides with the best geometry for sulfide-hydroxyl interaction are also the substrates which react most rapidly with singlet oxygen to give oxidation products. In addition, sulfone yields are in excess of 50% for the hydroxy-substituted sulfides but less than 5% for their hydrocarbon analogues. Several mechanisms that provide explanations for these unusually high sulfone yields are presented.
Preparation of ring-substituted (arylsulfonyl)cyclopropanes and (arylsulfonyl)bicyclobutanes from .gamma.,.delta.-epoxy sulfones
作者:Yehiel Gaoni
DOI:10.1021/jo00134a012
日期:1982.6
GAONI, Y., J. ORG. CHEM., 1982, 47, N 13, 2564-2571