Synthesis and reactions of some spiro[2H-chromen-2,1′-cycloalkanes]

Abstract

Spiro[2H-chromen-2,1′-cyclopentane] and the analogous cyclohexane and cycloheptane compounds have been prepared from the corresponding cycloalkanones. Reactions of the chromens with halogens and some chemistry of the derived products are described. The dehalogenation of an α-bromoketone by sodium borohydride in boiling methanol is reported. 3,4-Epoxyspiro[chroman-2,1′-cycloalkanes] have been obtained and ring-opened. The effects of the size of the spiro-annelated ring are minimal.