94532-19-1Relevant academic research and scientific papers
INTRAMOLECULAR FREE RADICAL CYCLISATIONS ONTO VINYL ETHERS. A METHOD FOR THE SYNTHESIS OF β-OXY-γ-BUTYROLACTONES
Ladlow, Mark,Pattenden, Gerald
, p. 4317 - 4320 (1984)
Radical cyclisation of the vinyl ether bromides (2) and (7) in the presence of tri-n-butylstannane produces precursors to the β-oxy-γ-butyrolactones (6) and (9) in high yields (>80percent).By contrast, treatment of (2) and (7) with bis-(dimethylglyoximato)(pyridine)cobalt(I) chloride followed by oxidation of the intermediates (5) and (11) led to the corresponding unsaturated β-oxy-γ-butyrolactones (4) and (12) respectively.
The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: Reaction development, scope, and applications
Ebner, David C.,Bagdanoff, Jeffrey T.,Ferreira, Eric M.,McFadden, Ryan M.,Caspi, Daniel D.,Trend, Raissa M.,Stoltz, Brian M.
supporting information; experimental part, p. 12978 - 12992 (2010/06/19)
The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23°C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-toexcellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
Intramolecular Free Radical Cyclisations onto Enol Ethers. A General Synthesis of α-Alkyl-β-oxy- and α-Methylene-β-oxy-γ-butyrolactones
Begley, Michael J.,Landlow, Mark,Pattenden, Gerald
, p. 1095 - 1106 (2007/10/02)
Radical cyclisation of the enol ether bromoacetals (26), (28a-c), (29), and (37) in the presence of tributylstannane, produces precursors to the β-oxy-γ-butyrolactones (33), (34a-c), (35), and the α-methylene-β-oxy-γ-butyrolactone (39) in high overall yields.By contrast, treatment of (26) and (28a-b) with the cobalt(I) reagent derived from bis(dimethylglyoximato)(pyridine)cobalt(III) chloride (40), followed by oxidation of the intermediates (43) leads to the corresponding unsaturated β-oxy-γ-butyrolactones (42).
