Intra- and intermolecular hetero-Diels-Alder reactions. 16. Stereospecificity in intramolecular hetero-Diels-Alder reactions of 2-benzylidene-1,3-dicarbonyl compounds
Stereospecific, R2AlCl-Promoted Intramolecular Ene Reaction of a 1,6-Dienoate: Evidence for a Concerted Mechanism
作者:Wolfgang Oppolzer、Sohail Mirza
DOI:10.1002/hlca.19840670312
日期:1984.5.2
provided in high yield the ene product 9 containing 83% 13C localized in the olefinic C(8)-methylene group. Accordingly, H-transfer occurs exclusively from the trans-methyl group of 7, consistent with a concerted ene process 7 9 thereby ruling out an intermediate cation 8 (Scheme 4).