38574-56-0Relevant academic research and scientific papers
Preparation of substituted enol derivatives from terminal alkynes and their synthetic utility
DeBergh, John R.,Spivey, Kathleen M.,Ready, Joseph M.
supporting information; experimental part, p. 7828 - 7829 (2009/02/01)
Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes. Specifically, terminal alkynes are known to undergo Cp2ZrCl2-catalyzed methylalumination. Here, we show that the resultant vinylalanes can be oxygenated with peroxyzinc species to generate trisubstituted enolates. Electrophilic trapping with carboxylic anydrides or silyl triflates yields trisubstituted enol esters or silanes, respectively. The tandem carbometalation/oxygenation tolerates free and protected alcohols, heterocycles, olefins, and nitriles. Stereodefined enol esters can undergo asymmetric dihydroxylation to yield optically active α-hydroxy aldehydes. Reduction with NaBH4 provides the diols of 1,1-disubstituted olefins in excellent ee. An application of this methodology to the enantioselective synthesis of the insect pheromone frontalin is presented. Finally, α-hydroxy aldehydes are shown to undergo homologation to a terminal alkyne, reductive amination, oxidation and olefination. Preliminary results indicate that tandem carbometalation/amination can be accomplished with azodicarboxylates. In this way, ene-hydrazines are formed in excellent yield. Copyright
Preparation of enantiopure butane-2,3-diacetals of glycolic acid and alkylation reactions leading to α-hydroxyacid and amide derivatives
Ley, Steven V.,Diez, Elena,Dixon, Darren J.,Guy, Richard T.,Michel, Patrick,Nattrass, Gillian L.,Sheppard, Tom D.
, p. 3608 - 3617 (2007/10/03)
The preparation of butane-2,3-diacetal protected glycolic acid and related systems is described together with highly selective alkylation reactions of (R,R) and (S,S) butanediacetal protected glycolic acid. These compounds are readily deprotected to give
Butane-2,3-diacetal-desymmetrized glycolic acid - A new building block for the stereoselective synthesis of enantiopure α-hydroxy acids
Diez, Elena,Dixon, Darren J.,Ley, Steven V.
, p. 2906 - 2909 (2007/10/03)
According to a chiral memory protocol, a chiral glycolic acid equivalent, the butane-2,3-diacetal-desymmetrized glycolate 2, is obtained from chiral 3-halopropane-1,2-diols 1. Compound 2 is a new and effective building block for the synthesis of mono- and
ASYMMETRIC SYNTHESIS OF (R)- AND (S)-CITRAMALATE IN HIGH ENANTIOMERIC PURITY
Frye, Stephen V.,Eliel, Ernest L.
, p. 3907 - 3910 (2007/10/02)
An asymmetric synthesis of both isomers of dimethyl 2-acetoxycitramalate in over 96percent enantiomeric excess is described.
