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Synfacts 2010(4): 0407-0407  
DOI: 10.1055/s-0029-1219502
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Iodocyclization-Based Synthesis of Spiro Heterocycles

Contributor(s): Victor Snieckus, Johnathan Board
T. Okitsu, D. Nakazawa, A. Kobayashi, M. Mizohata, Y. In, T. Ishida, A. Wada*
Kobe Pharmaceutical University and Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
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Publication History

Publication Date:
22 March 2010 (online)

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Significance

Reported is the spirocyclization of ortho-alkoxy N- and O-propargyl anilines and phenols. This process is mediated by a combination of NIS and BF3˙OEt2, both of which are necessary for satisfactory yields. The reaction appears to tolerate a reasonable range of nitrogen substituents; however, it is not so tolerant of alkynyl analogues, since the reaction fails when R¹ = n- or t-Bu. When aromatic propargyl ethers are used the products undergo spontaneous ­Diels-Alder reactions to give very interesting complex products. These were further elaborated through Stille and Sonogashira cross-coupling chemistry.