Symbiotic reagent activation: Oppenauer oxidation of magnesium alkoxides by silylglyoxylates triggers second-stage aldolization
- PMID: 16848444
- PMCID: PMC1868421
- DOI: 10.1021/ja062637+
Symbiotic reagent activation: Oppenauer oxidation of magnesium alkoxides by silylglyoxylates triggers second-stage aldolization
Abstract
The treatment of silylglyoxylates with magnesium alkoxides at ambient temperature results in symbiotic Oppenauer oxidation of the alkoxide and Meerwein-Ponndorf-Verley reduction of the silylglyoxylate. The reduced silylglyoxylate undergoes subsequent [1,2]-Brook rearrangement and aldol reaction with the carbonyl oxidation product. The magnesium alkoxide may be accessed via deprotonation of primary or secondary alcohols with EtMgBr, via addition of Grignard reagents to aldehydes, or via CuI-catalyzed alkylation of epoxides. For aliphatic primary alkoxides, moderate levels of anti diastereoselection are observed. A crossover experiment reveals that dissociation of the nascent aldehyde from the magnesium center is faster than [1,2]-Brook rearrangement and aldolization.
References
-
- Mahrwald R, editor. Modern Aldol Reactions. Wiley-VCH; Weinheim, Germany: 2004.
-
-
For leading references, see: Yoshikawa N, Yamada YMA, Das J, Sasai H, Shibasaki M. J Am Chem Soc. 1999;121:4168–4178.Taylor SJ, Morken JP. J Am Chem Soc. 1999;121:12202–12203.List B, Lerner RA, Barbas CF., III J Am Chem Soc. 2000;122:2395–2396.Trost BM, Ito H. J Am Chem Soc. 2000;122:12003–12004.Northrup AB, MacMillan DWC. J Am Chem Soc. 2002;124:6798–6799.Jang HY, Huddleston RR, Krische MJ. J Am Chem Soc. 2002;124:15156–15157.Evans DA, Downey CW, Hubbs JL. J Am Chem Soc. 2003;125:8706–8707.Ooi T, Kameda M, Taniguchi M, Maruoka K. J Am Chem Soc. 2004;126:9685–9694.
-
-
-
For a recent example, see: Kagawa N, Ihara M, Toyota M. Org Lett. 2006;8:875–878.
-
-
- Bolm C, Kasyan A, Heider P, Saladin S, Drauz K, Guenther K, Wagner C. Org Lett. 2002;4:2265–2267. - PubMed
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources