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New functional allylic lithium reagents: gem-dialkoxyallyllithium reagents: a useful route to β-silyl- and β-stannylpropionate esters

1980; Elsevier BV; Volume: 194; Issue: 1 Linguagem: Inglês

10.1016/s0022-328x(00)90330-9

1872-8561

Dietmar Seyferth, Robert E. Mammarella, Helmut Alfons Klein,

Advanced Synthetic Organic Chemistry

The reaction of sec-butyllithium with acrolein dialkyl acetals in THF or in THF/Et2O/pentane at -95°C results in formation of gem-dialkoxyallyllithium reagents, Li[CH2CHC(OR)2]. These react with organosilicon and organotin chlorides to give ketene acetals, R3SiCH2CHC(OR)2 and R3SnCH2CHC(OR)2. The acid hydrolysis of these products produces β-substituted propionic acid esters, R3SiCH2CH2CO2R and R3SnCH2CH2CO2R. Reactions of these lithium reagents with allyl bromide gave esters of 5-hexonoic acid, CH2CH(CH2)3CO2R (R = Me, Et).