Abstract
A series of three chromium tricarbonyl benzaldehyde acetal complexes were prepared from benzaldehyde diethyl acetal and (+)-diethyl tartrate. These compounds were ortho-lithiated by a number of bases, and the diastereoselectivity of lithiation was determined by quenching of the resulting anions with Me3SiCl. Complexes 1 and 2 were found to give moderate levels of diastereoselection, while the combination of complex 3 and 2.4 equiv of n-BuLi under equilibrating conditions gave an 86% de of silylated products. Other electrophiles gave slightly higher de's (88% to ≥94%), and all products derived from 3 were separable by column chromatography. Hydrolysis of the ortho-methylated product to the corresponding benzaldehyde complex (−)-21 as well as X-ray structural analysis of the trimethylsilylated complex demonstrated that preferential pro-R deprotonation had occurred.
Original language | English |
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Pages (from-to) | 6182-6189 |
Number of pages | 8 |
Journal | Journal of Organic Chemistry |
Volume | 58 |
Issue number | 23 |
DOIs | |
Publication status | Published - 1993 Jan 1 |
Externally published | Yes |
ASJC Scopus subject areas
- Organic Chemistry