Application of the method of molecular rotation differences in structural and stereochemical problems in triterpenes
作者:L. Ogunkoya
DOI:10.1016/0040-4020(77)80158-0
日期:1977.1
pentacyclic triterpenoid alcohols and their simple derivatives have been correlated by the Barton and Jones Method of MolecularRotationDifferences (MRD). By so doing, all the known compounds have been divided into nineteen stereoskeletal types with diagnostic, in some cases, values of MRD New generalisations are made on the application of this method to the elucidation of structures of triterpenoids. Cases
The intramolecular cooperative reactions of 1,2-bis(diazoketone)s initiated by the Wolff rearrangement of alpha-diazoketones have been investigated. Under thermal conditions, 1,2-bis(diazoketone)s are efficiently transformed into 2-cyclopenten-1-one derivatives with complete stereospecificity. Thus, a most extraordinary result is reported, that trans-hydro-2-inden-1-ones (1-3) were synthesized for the first time from trans-1,2-bis(diazoketone)s (5, 11, and 12), respectively. The unprecedented trans-hydroindenone structure was confirmed by X-ray analysis of 3 as well as H-1 NMR analysis and was supported by ab initio molecular orbital calculations. The same reactions were also carried out under photochemical conditions and were applied to 1,3-bis(diazoketone)s, giving 2-cyclohexen-1-one derivatives.
BRADSHAW J. S.; CAMPBELL M. L.; HASSELL L. A.; BAXTER J. K., J. HETEROCYCL. CHEM., 1979, 16, NO 4, 721-723
作者:BRADSHAW J. S.、 CAMPBELL M. L.、 HASSELL L. A.、 BAXTER J. K.