We describe a novel reagent system to obtain acyl fluorides directly from three different functional group precursors: carboxylic acids, aldehydes, or alcohols. The transformation is achieved via a combination of trichloroisocyanuric acid and cesium fluoride, which facilitates the synthesis of various acyl fluorides in high yield (up to 99%). It can be applied to the late-stage functionalization of
Stereoselective synthesis of β,ε-dihydroxy-α-amino acids by ring opening of 4,5-dihydroisoxazolyl derivatives
作者:Giuseppe Cremonesi、Piero Dalla Croce、Francesco Fontana、Claudio Fiorelli、Concetta La Rosa
DOI:10.1016/j.tetasy.2008.11.034
日期:2008.12
Enantiomerically pure β-(4,5-dihydroisoxazol-3-yl)-substituted β-hydroxy-α-amino acids were synthesised stereoselectively by means of an addition reaction between (5,5-disubstituted-4,5-dihydroisoxazol-3-yl)-carbaldehydes and (R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine (Schöllkopf’s reagent) as a chiral auxiliary. The addition gave mixtures of only two adducts with high diastereoselectivity. The