178976-47-1Relevant academic research and scientific papers
Stereoselective synthesis of chiral polyfunctionalized cyclohexane derivatives. Palladium(II)-mediated reaction between cyclohexenones and diazomethane
Rodríguez-García, Cristóbal,Ibarzo, Javier,álvarez-Larena, ángel,Branchadell, Vicen?,Oliva, Antoni,Ortu?o, Rosa M
, p. 1025 - 1034 (2007/10/03)
Several chiral polyfunctionalyzed cyclohexanones and cyclohexenones have been synthesized through Diels-Alder cycloadditions, stereoselectivity being stated by X-ray structural analysis and NOE experiments. The chemoselectivity in the palladium(II)-catalyzed reaction between cyclohexenones and diazomethane has been investigated. Thus, in those enones bearing an amide function on the γ-carbon, the preferential addition occurs at the carbonyl giving epoxides which, under acid conditions, rearrange to tetrahydrobenzoxazoles. The other cyclohexenones afford cyclopropanes as a result of addition to the C=C bond. A mechanistic approach to explain the whole process is proposed.
Synthesis of constrained prolines by Diels-Alder reaction using a chiral unsaturated oxazolone derived from (R)-glyceraldehyde as starting material
Bu?uel, Elena,Gil, Ana M,Díaz-De-Villegas, María D,Cativiela, Carlos
, p. 6417 - 6427 (2007/10/03)
This report describes a new route for the asymmetric synthesis of enantiomerically pure 2-substituted 7-azabicyclo[2.2.1]heptane-1-carboxylic acids, which are new conformationally constrained β-functionalised proline analogues. Our strategy is based on the preparation of a valuable azabicyclic intermediate by a key step that involves the intramolecular cyclisation of a derivative obtained from the transformation of the adducts provided by the asymmetric Diels-Alder reaction of a chiral oxazolone derived from (R)-glyceraldehyde with Danishefsky's diene. The application of this procedure to the synthesis of (1S,2R,4R)-7-azabicyclo[2.2.1]heptane-1,2-dicarboxylic acid and (1S,2R,4R)-2-propyl-7-azabicyclo[2.2.1]heptane-1-carboxylic acid hydrochlorides, which can be also considered as L-aspartic acid and L-norleucine analogues respectively, is useful to illustrate the versatility of our methodology.
Z-2-phenyl-4-[(S)-2,2-dimethyl-1,3-dioxolan-4-ylmethylen]-5(4H)-oxazolone as the dienophile in asymmetric Diels-Alder reactions. II
Bunuel, Elena,Cativiela, Carlos,Diaz-De-Villegas, Maria D.
, p. 1431 - 1436 (2007/10/03)
Diels-Alder reaction of Z-2-phenyl-4-[(S)-2,2-dimethyl-1,3-dioxolan-4-ylmethylen]-5(4H)-oxazolone and Danishefsky's diene is studied. Thermally induced reaction took place at room temperature with a high diastereofacial selectivity and Diels-Alder adducts
