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

C Gómez, DJ Ramón, M Yus

Index: Gomez, Cecilia; Ramon, Diego J.; Yus, Miguel Tetrahedron, 1993 , vol. 49, # 19 p. 4117 - 4126

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Citation Number: 49

Abstract

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.