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- Manner, Sophie, et al.
(författare)
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Asymmetric baker's yeast reductions of bridgehead-substituted bicyclo[2.2.2]octane-2,6-dione derivatives followed by conversion into catalytically active BODOLs for the diethylzinc addition to benzaldehyde.
- 2010
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Ingår i: Tetrahedron. - : Elsevier Ltd.. - 0957-4166 .- 1362-511X. ; 21:11-12, s. 1374-1381
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Tidskriftsartikel (refereegranskat)abstract
- 4-Substituted bicyclo[2.2.2]octane-2,6-diones I [R = acetyl, benzyl, allyl, etc.] have been synthesized and tested as substrates in the enantioselective redn. with baker's yeast to give the corresponding hydroxy ketones II [R = acetyl, benzyl, allyl, etc.]. It was found that the deriv. bearing a TIPSO group at the 4-position was not reduced at all while that with a TBDMSO group gave 87% yield and 46% ee. Other 4-oxy functionalized derivs. were reduced with varying yields (36-87%) and ees (10-82%). The best result was obtained for the 4-Oallyl deriv. (80% yield, 82% ee). The hydroxy ketones carrying the benzyloxy and allyloxy groups at the 4-position were converted into the corresponding BODOLs III [R = allyl, benzyl], which were tested as catalysts in the diethylzinc addn. to benzaldehyde. In this reaction the ees were 90% and 89%, resp., which showed that BODOLs substituted at the 4-position are essentially as good catalysts in this reaction as those bearing a hydrogen. [on SciFinder(R)]
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