RESUMEN
An efficient method for the preparation of highly optically active 3-allenyl- and 3-vinyl-4-aminochromanes by In-mediated intramolecular cyclization has been developed. The synthetic utilities of the approach were demonstrated by the construction of various chiral polycyclic heterocycles, especially the interesting spiroheterocyclic compound 9 and steroid analogue 10.
Asunto(s)
Cromanos/síntesis química , Compuestos Heterocíclicos de 4 o más Anillos/síntesis química , Iminas/química , Indio/química , Compuestos de Sulfonio/química , Catálisis , Cromanos/química , Ciclización , Compuestos Heterocíclicos de 4 o más Anillos/química , Estructura Molecular , EstereoisomerismoRESUMEN
The domino effect: An efficient and general catalytic one-pot synthesis of quaternary-substituted isochroman derivatives has been developed (see scheme). The cascade transformation relies on rhodium-catalyzed highly regio- and enantioselective 1,2-addition of arylboronic acids to unsymmetrical α-diketones and intramolecular etherification or esterification, and provides a variety of enantioenriched isochromanones under exceptionally mild conditions.
Asunto(s)
Cromonas/síntesis química , Cetonas/química , Compuestos Organometálicos/química , Rodio/química , Catálisis , Cromonas/química , Estructura Molecular , Fenómenos Ópticos , EstereoisomerismoRESUMEN
The first example of catalytic asymmetric 1,2-addition of arylboronic acids to heteroaryl α-ketoesters has been developed for the highly efficient and enantioselective synthesis of quaternary carbon-containing heteroaromatic α-hydroxy esters. The reaction works well with a variety of α-ketoesters including 3-indoleglyoxylates, 3-benzofuranglyoxylates and 3-benzothiopheneglyoxylates under very mild conditions, affording the corresponding products in moderate to good yields with high enantiomeric excesses (up to 97%).
Asunto(s)
Ácidos Borónicos/química , Ésteres/síntesis química , Cetonas/química , Rodio/química , Catálisis , Glioxilatos/química , Indoles/química , Espectroscopía de Resonancia Magnética , EstereoisomerismoRESUMEN
A pincer-like chiral auxiliary strategy for synthesizing various optically active α,α-disubstituted amino acids in high yields with excellent enantioselectivities is described.
Asunto(s)
Aminoácidos/química , Compuestos de Amonio Cuaternario/química , Compuestos de Amonio Cuaternario/síntesis química , Solventes/química , Estereoisomerismo , TemperaturaRESUMEN
The design and development of an extraordinarily interesting new class of chiral sulfur-olefin hybrid ligands with remarkable structural simplicity were described. These unique sulfinamide-olefin ligands have been proved to be highly effective ligands in rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids to α,ß-unsaturated carbonyl compounds (up to 99% yield and 98% ee).
Asunto(s)
Alquenos/química , Amidas/química , Cinamatos/química , Azufre/química , Catálisis , Ligandos , Estructura Molecular , EstereoisomerismoAsunto(s)
Alquenos/química , Ácidos Borónicos/química , Cetonas/química , Rodio/química , Azufre/química , Catálisis , Ligandos , EstereoisomerismoRESUMEN
The design and development of a novel class of chiral sulfur-olefin hybrid ligands with high synthetic feasibility are described. These new sulfoxide-olefin ligands showed excellent catalytic activities and enantioselectivities (up to 98% ee) in rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids to α,ß-unsaturated carbonyl compounds.