59339-53-6Relevant academic research and scientific papers
Chemoenzymatic approach to optically active phenylglycidates: Resolution of bromo- and iodohydrins
Anand, Naveen,Kapoor, Munish,Koul, Surrinder,Taneja, Subhash C.,Sharma, Rattan L.,Qazi, Ghulam N.
, p. 3131 - 3138 (2004)
Enantiomerically enriched phenylglycidates, precursors of the taxol C-13 phenylisoserine side chain and diltiazem, were prepared by kinetic resolution of anti-2-bromo-3-hydroxy- and anti-3-hydroxy-2-iodophenylpropanoates to provide enantioriched (2R,3R)- and (2S,3S)-halohydrins. The bulkiness and inflexibility of bromo and iodo groups in halohydrins have made them inaccessible to the active site of most of the lipases utilized for the hydrolysis of their acyloxy derivatives. In a set of 22 hydrolases screened herein, including native as well as commercial enzymes, only Aspergillus niger (Lipase AS, AMANO) could catalyze the hydrolysis with high enantioselectivity (E = 176). The resolved halohydrins easily underwent transformation to the corresponding (2S,3R)- and (2R,3S)-phenylglycidates.
Mechanism of Dehydroacetoxylation of Methyl 3-Acetoxy-3-aryl-2-halogenopropanoates
Cabaleiro, Mercedes C.,Garay, Raul O.
, p. 1091 - 1096 (2007/10/02)
The rate of sodium methoxide-induced dehydroacetoxylation of the diesters p-RC6H4CH(OAc)CXHCO2Me (X= Br or Cl) has been studied as a function of the para-substituent.The results correspond to the para-substituent effects expected for proton abstraction from C-2, as estimated from the diastereoisomerisation of model compounds under similar conditions.This suggests that the elimination occurs via a carbanion mechanism, with C(2)-H bond-breaking rate-determining.The apparent insensitivity of the kinetic behaviour to configuration differences, together with the response of the reactions to the effect of the 3-substituent, is interpreted in terms of inductive stabilisation by the 2-halogen atom, which tends to localise the incipient negative charge at C-2, inhibiting distortion of its tetrahedral geometry.
