NOVEL RING-ENLARGEMENT CHAIN-EXTENSION REACTION

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A novel ring expansion and chain extension reaction has been discovered. The new reaction is completely regiospecific, takes place in excellent yield and appears to be capable of very broad application and extension, particularly in the area of medium- sized rings. Accordingly, it is proposed to extend the method to include heterocyclic compounds with emphasis on the pharmacologically useful benzazepines and dibenzazepines. Application to the synthesis of optically active beta-amino acids will be explored. Vinylogous ring expansion and inter- and intramolecular olefin trapping experiments will be carried out. The latter can yield new, efficient annulation methods. In addition to developing the one-carbon ring expansion, preliminary experimental findings have given positive results for three- and four-carbon ring expansions which open many new opportunities. These coupled with multiple ring expansion of keto diesters and diketo tetraesters provide a wealth of opportunity for elaboration of single and fused medium ring systems. The mechanistic premises underlying the reaction will also be examined.