Synthetic Approaches to Pentacyclic Triterpenes of the Arborane Family. II Tetracyclic Intermediates

ARSENIYADIS, S.; RODRIGUEZ, R.; SPANEVELLO, R. A.; CAMARA J.; THOMPSON, A.; OURISSON, G.

TETRAHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 1992 vol. 48 p. 1255 - 1262

0040-4020

Diels-Alder condensation of the bicyclic diene 1 with 2,6-dimethylbenzoquinone 2 under thermal and Lewis acid-catalyzed conditions gives the diastereomers 3, 4, 5 and 8; their structures are demonstrated by NMR analysis, in full agreement with the conformations deduced from molecular mechanic