Studies on the nucleophilic substitution reactions of a dimeric cyclopentadienone

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Nucleophilic substitution reactions of 3,5-Dibromo-3a,4,7,7a-tetrahydro-4,7-methano-indene-1,8-dione (48) have been studied. Amines, thiols and alcohols have been employed, with considerable success, as nucleophilic agents and gave vinylogus amides, thioesters and esters, respectively. Among the former, the secondary amines gave best results, while primary amines were found to be ill-suited as nucleophiles for this substrate. Aromatic thiols proved more amenable than the aliphatic ones. Base catalysis was used with amines and thiols, while alcohols worked well under acid-catalysed conditions. Microwave decarbonylation of the vinylogous amides did not yield the desired indanones. Enantioselective dimerization to procure 48 was attempted in the presence of some modified cinchona alkaloids and resulted in a slight excess of one of the enantiomers.