Reductive opening of 2-phenyl-1,3-dioxolanes by a naphthalene-catalysed lithiation: synthetic applications
1993; Elsevier BV; Volume: 49; Issue: 42 Linguagem: Inglês
10.1016/s0040-4020(01)80223-4
ISSN1464-5416
AutoresJ. F. GIL, Diego J. Ramón, Miguel Yus,
Tópico(s)Chemical Reaction Mechanisms
ResumoThe reaction of 2-phenyl-1,3-dioxolanes 1a,b with an excess of lithium powder in the presence of a catalytic amount of naphthalene (4 mol %) in tetrahydrofuran at −40°C followed by successive reaction with an electrophile and final hydrolysis with water at the same temperature yields the corresponding monoprotected 1,2-diols 2aa-2bf. The same process but allowing to rise the temperature to 20°C before the hydrolysis affords alcohols 3aa-3bd. The use of 2,2-diphenyl-1,3-dioxolane 1d, under similar reaction conditions as for compounds 2, permits the isolation of 2,2-diphenylalcohols 11da-11dc, resulting from the reaction with two different electrophiles. A mechanistic rationalization for all processes is given.
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