Takai K, Morita R, Matsushita H, Toratsu C. Cross-pinacol-type coupling reactions between alpha,beta-unsaturated ketones and aldehydes with low-valent metals.
Chirality 2003;
15:17-23. [PMID:
12467037 DOI:
10.1002/chir.10148]
[Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Treatment of an alpha,beta-unsaturated ketone and an aldehyde with chromium(II) chloride and R(3)SiCl in DMF gives cross-pinacol-type coupling products, 1,2-diols selectively. The anti/syn ratios of the produced 1,2-diols are shown to depend on the reaction temperature: at lower temperatures, the anti adduct is produced selectively, but at higher temperatures, the anti/syn ratios gradually decrease. When a combination of manganese and a catalytic amount of lead are used instead of chromium(II), 1,6-diketone, a dimer of the alpha,beta-unsaturated ketone, is produced selectively.
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