Symbiotic reagent activation: Oppenauer oxidation of magnesium alkoxides by silylglyoxylates triggers second-stage aldolization.
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.
Linghu
Xin
X
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Satterfield
Andrew D
AD
Johnson
Jeffrey S
JS
D000447:Aldehydes / Q000737:chemistry*; D006038:Glyoxylates / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D017655:Silicon Compounds / Q000737:chemistry*
D000447:Aldehydes; D006038:Glyoxylates; D017616:Magnesium Compounds; D017655:Silicon Compounds; C116609:3-hydroxybutanal