1999 年 57 巻 3 号 p. 170-180
New and useful reactions utilizing the characteristics of gem-dihalocyclopropanes and halocyclopropanes are developed from the many-sided cationic approaches toward versatile benzannulations. Regioselective and alternative naphthalene-benzannulations of aryl (gem-dihalogenocyclopropyl) methanols and Aryl1 (aryl2) (gem-dichlorocyclopropyl) methanols were performed for the syntheses of various types of both “symmetrically” and “unsymmetrically” substituted and α-and β-halogenonaphthalenes by choosing either the order of the reaction sequences or the catalysts. Sequential and regioselective Friedel-Crafts reactions (naphthol-benzannulations) of gem-dichlorocyclopropanecarbonyl chlorides produced various 4-aryl-1-naphthol derivatives straightforwardly (in a one-pot manner) via significantly different mechanisms from the related naphthalene-benzannulations. These utilities could be demonstrated by the total synthesis of five natural lignan lactones and their analogs. A related 2, 5-diaryl-furan syntheses, a novel cyclopropane-shift type benzannulation, and a unique chirality transfer from optically active gem-dichlorocyclopropanes into atropisomeric 1-arylnaphthalenes were also described. The variation in a variety of reactions is unequivocally due to the high degree of site-selectivity in the cyclopropane-ring-openings of the three bonds (bonds A, B, and C).