1,6-Conjugate-Addition-Induced [2+1] Annulation of para-Quinone Methides and Pyrazolones: Synthesis of Bis-Spiro Compounds with Contiguous Quaternary Spiro-Centers

摘要

A diastereoselective formal 1,6-conjugate-addition-mediated [2 + 1] annulation reaction using p-quinone methides and pyrazolones has been described. The corresponding bis-spiro[cyclohexadienone-cyclopropane-pyrazolone] compounds were obtained in very good yield under mild reaction conditions.