Activated Basic Alumina Promotes a Mild, Clean and High-Yield Racemization-Free Synthesis of t-Butyl Esters from Chiral Acid Bromides and t-Butyl Alcohol
Esterification of a variety of acid bromides having even steric bulkiness with t-BuOH/activated basic alumina gave the corresponding t-butyl esters in good to excellent yields.In the case of chiral acid bromides, no racemization has been ascertained for the first time.
STEREOCHEMICAL OBSERVATIONS IN THE SYNTHESIS OF NOVEL 1,4,5,9b-TETRAHYDRO-5-PHENYL-2H-AZETOIOSQUINOLIN-2-ONE DERIVATIVES
Imine (5) reacted with Cl2CHC(O)Cl in the presence of Et3N to give β-lactams (7a) and (7b) in a 4:1 ratio.The stereochemistry of cycloadduct (7a) was confirmed by X-ray analysis.Uncyclized intermediates were identified.Reduction of dichloro β-lactam (7a) with Zn/HOAc gave mostly exo monochloride (13a), with high stereoselectivity (10:1 ratio).Reduction of a mixture of exo and endo monochlorides (13a) and (13b) with Zn/HOAc indicated that the more sterically hidered endo chlorine is preferentially attacked.Reduction of (7a) with Bu3SnH gave β-lactam (14a) as the major product.
Nortey, Samuel O.,McComsey, David F.,Maryanoff, Bruce E.
p. 1075 - 1088
(2007/10/02)
Oxidation of halo-olefins
Process for the non-catalytic liquid phase oxidation of halo-olefins, having 2 to 7 carbon atoms, by O2 at elevated temperatures and pressures to produce oxygenated organic products having the same number of carbon atoms as the starting material.
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(2008/06/13)
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