Naphthalene-catalysed lithiation of 3-chloro-2-chloromethylpropene in a Barbier-type process with carbonyl compounds

Article abstract of DOI:10.1016/S0040-4020(01)89923-3

The reaction of 3-chloro-2-chloromethylpropene (1) and carbonyl compounds (2) with an excess of lithium powder in the presence of a catalytic amount of naphthalene (6%) in tetrahydrofuran at -78 to 20°C leads, after hydrolysis, to the corresponding methylenic 1,5-diols 3 in a Barbier-type process. The treatment of the crude diols 3 with 12 M. hydrochloric acid affords selectively the corresponding substituted dihydropyrans 6.