作者:Deborah A. Smithen、Christopher J. Mathews、Nicholas C. O. Tomkinson
DOI:10.1039/c2ob25293g
日期:——
Reaction of cyclic ketones with chiral N-alkyl-O-acyl hydroxylamines leads to the corresponding α-oxyacylated carbonyl compound in up to 89% ee. The levels of asymmetric induction were influenced by solvent polarity, acid strength and, to a lesser extent, temperature. Increasing the steric bulk around the nitrogen atom of the hydroxylamine reagent led to increased levels of asymmetric induction, which was also found to be detrimental to the yield observed for the transformation. Examination of N- and O-substituents along with substrates revealed the scope and limitations of the procedure.
Direct Asymmetric α Benzoyloxylation of Cyclic Ketones
作者:Olga Lifchits、Nicolas Demoulin、Benjamin List
DOI:10.1002/anie.201104244
日期:2011.10.4
business: A readily available cinchona‐derived primary amine is an effective catalyst for the directasymmetricαbenzoyloxylation of cyclicketones (see scheme; Bz=benzoyl). This efficient and highly enantioselective method uses inexpensive benzoyl peroxide as the oxygen source and stoichiometric amounts of the ketone, and expands the current set of methodologies to directly access valuable protected 2‐hydroxyketone
Enantioselective Synthesis and Stereoselective Rearrangements of Enol Ester Epoxides
作者:Yuanming Zhu、Lianhe Shu、Yong Tu、Yian Shi
DOI:10.1021/jo001593z
日期:2001.3.1
Enolesters can be epoxidized with high enantioselectivities using the fructose-derived chiral ketone 1 as catalyst and Oxone as oxidant. A detailed study of enantiomerically enriched enolesterepoxides has revealed that the acid-catalyzedrearrangement can proceed through two distinct pathways, one with retention of configuration and the other with inversion. The competition between the two pathways