15763-62-9Relevant articles and documents
Synthesis of α-difluoro and α-difluoro-β-trifluoroketo-derivatives as potential inhibitors for cholesterol ester hydrolase
David, Beatrice,Schuber, Francis
, p. 1673 - 1676 (1996)
Pancreatic Cholesterol Ester Hydrolase, a serine esterase, catalyzes the hydrolysis of cholesteryl esters in the gut. We report the convergent synthesis of α-difluoro-β-trifluoroketo-(5,10,15) and of α-difluoroketo-derivatives (22,23) as inhibitors of this enzyme that were designed to generate stable tetrahedral reaction intermediates.
Modified McFadyen-Stevens reaction for a versatile synthesis of aliphatic/aromatic aldehydes: Design, optimization, and mechanistic investigations
Iwai, Yuri,Ozaki, Takashi,Takita, Ryo,Uchiyama, Masanobu,Shimokawa, Jun,Fukuyama, Tohru
, p. 1111 - 1119 (2013/06/04)
The traditional McFadyen-Stevens reaction requires harsh alkaline reaction conditions, thus precluding application to the synthesis of aliphatic aldehydes. Our modified McFadyen-Stevens reaction enables the transformation from the N,N-acylsulfonyl hydrazine to the corresponding aldehyde upon treatment with an imidazole-TMS imidazole combination without relying on oxidative or reductive reagents. The reduced basicity and in situ protection of the resulting aldehyde widens the substrate scope to include aliphatic aldehydes, even ones bearing an α-hydrogen atom. Close examination of the side reactions for particular substrates in combination with theoretical considerations via DFT calculations led to a mechanistic understanding of the McFadyen-Stevens reaction involving an acyl diazene and a hydroxy carbene as reasonable intermediates.
Stereoselective synthesis of cyclopropanes based on a 1,2-chirality transfer
Muehling, Olaf,Wessig, Pablo
supporting information; experimental part, p. 7951 - 7960 (2009/10/23)
A stereoselective route to enantiomerically enriched bicyclic cyclopropane derivatives 13 is described which is based on a conceptually novel 1,2-chirality transfer approach. The hyperconjugative interaction of an electronically excited carbonyl group with the σ* orbital of an adjacent C-X bond in the transition state of a hydrogen abstraction causes the preference of a certain conformation and consequently the differentiation between two diastereotopic methylene groups. The 1,2-chirality transfer is completed by a subsequent HX elimination which destroys the only stereogenic center in the reactants 12. Furthermore, it was found that contrary enthalpic and entropic influences result in the existence of an inversion temperature T0. Upon crossing T0 the stereoselectivity is reversed. Considering this temperature dependency, chirality transfer efficiencies of up to 83% could be achieved. The absolute configuration of most products could be unambiguously determined by VCD spectroscopy combined with DFT calculations.
