Functionalized arenes were prepared by chelation-controlled [3 + 3] cyclization/cyclopropane opening reactions of 1-trimethylsilyloxy-1,3-butadienes with benzyloxy- or methoxy-substituted 1,1-diacylcyclopropanes. A number of benzyloxy-substituted derivatives were transformed into isochromanes by deprotection and subsequent cyclization. Mixed chromanes-isochromanes were prepared starting with 1,3-bis(silyloxy)-1,3-butadienes containing a remote chloride group.

No abstract

Homophthalates were prepared by formal [3 + 3] cyclocondensation of 1,3-bis(silyl enol ethers) with silylated methyl 3,5-dioxohexanoate.

2008 Monovalent phenols Q 0180Chelation Control in the [3 + 3] Annulation Reaction of Alkoxy-Substituted 1,1-Diacylcyclopropanes with 1,3-Bis(trimethylsilyloxy)-1,3-butadienes. -The reaction of cyclopropanones of type (III) with bissiloxy-substituted butadienes offers a convenient approach to highly functionalized phenols. Derivative (Va) is converted to the tetrahydrobenzofuran derivative (VII) by debenzylation and subsequent Williamson reaction. -(HEFNER, J.; LANGER*, P.; Tetrahedron Lett. 49 (2008) 29-30, 4470-4472; Inst. Chem., Univ. Rostock, D-18059 Rostock, Germany; Eng.) -Mais 42-058

3 Homophthalates (V) are prepared by [3 + 3] cyclocondensation reactions of 1,3‐bis(silyloxy)‐1,3‐butadienes with silylated methyl 3,5‐dioxohexanoate.