Regioselective synthesis of spiro[naphthalene-2(1H),3 '-[3H]pyrazol]-1-ones utilizing 1,3-dipolar cycloaddition of nitrilimines

摘要

1,3-Dipolar cycloaddition reaction of nitrilimines to a variety of 2-arylmethylidene-3,4-dihydro-1-naphthalenones 1a-h afforded the corresponding spiro[naphthalene-2(1 H),3'-[3H]pyrazol]-1-ones 3 and not the isomeric spiro[naphthalene-2(1H),4'-[4H]pyrazol]-1-ones 4, in high regioselectivity. The structure of the isolated products was established through different spectroscopic techniques and confirmed via HMBC. [References: 13]