Enantioselective Horner-Wadsworth-Emmons Reaction Using Chiral Lithium 2-Aminoalkoxides.
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چکیده
منابع مشابه
Unexpected epimerization at C2 in the Horner-Wadsworth-Emmons reaction of chiral 2-substituted-4-oxopiperidines.
The observed epimerization at C2 in the Horner-Wadsworth-Emmons (HWE) reaction of chiral 2-substituted-4-oxopiperidines has been investigated and, on the basis of the experimental results, a mechanism for this unexpected process has been proposed.
متن کاملUse of lithium hexafluoroisopropoxide as a mild base for Horner-Wadsworth-Emmons olefination of epimerizable aldehydes.
[reaction: see text] The weak base lithium 1,1,1,3,3,3-hexafluoroisopropoxide (LiHFI) is shown to be highly effective as a reagent for intermolecular Horner-Wadsworth-Emmons (HWE) olefination of epimerizable aldehydes with trimethyl phosphonoacetate, affording products with little or no epimerization and notably high E-selectivity.
متن کاملStereoselective synthesis of tetrasubstituted (Z)-alkenes from aryl alkyl ketones utilizing the Horner-Wadsworth-Emmons reaction.
Tetrasubstituted (Z)-alkenes were readily prepared through the Horner-Wadsworth-Emmons reactions of methyl 2-[bis(2,2,2-trifluoroethyl)phosphono]propionate with aryl alkyl ketones by employing Sn(OSO(2)CF(3))(2) and N-ethylpiperidine.
متن کاملHighly selective synthesis of (E)-alkenyl-(pentafluorosulfanyl)benzenes through Horner–Wadsworth–Emmons reaction
Diethyl 2-nitro-(pentafluorosulfanyl)benzylphosphonates, available by the vicarious nucleophilic substitution reaction of meta- and para-nitro-(pentafluorosulfanyl)benzenes and diethyl chloromethylphosphonate, undergo Horner-Wadsworth-Emmons reaction with aldehydes in the presence of potassium hydroxide in acetonitrile at ambient temperature to give (E)-2-nitro-1-alkenyl-(pentafluorosulfanyl)be...
متن کاملRoute to α-Aryl Phosphonoacetates: Useful Synthetic Precursors in the Horner–Wadsworth–Emmons Olefination
A versatile and general catalytic strategy has been developed for the α-arylation of phosphonoacetates utilizing parallel microscale experimentation. These α-substituted phosphonoacetates are widely useful, notably as substrates in the Horner-Wadsworth-Emmons-type olefinations. However, the current routes to these products involve harsh conditions, limiting the variety of functionality. The rep...
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ژورنال
عنوان ژورنال: Chemical and Pharmaceutical Bulletin
سال: 1997
ISSN: 0009-2363,1347-5223
DOI: 10.1248/cpb.45.753