S 98 Synthesis of chromeno[3,4-c][1,2]oxazine-N-oxides via formal [4+2] cycloaddition of 3-nitro-2-trihalomethyl-2H-chromenes with cyclohexanone and pinacolone enamines [Electronic resource] / V. Yu. Korotaev, A. Yu. Barkov, E. G. Matochkina, M. I. Kodess, V. Ya. Sosnovskikh // Tetrahedron. - 2014. - Vol.70, №34. - С. 5161-5167. - Bibliogr. : p. 5166-5167 (42 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): 2,3,4-TRISUBSTITUTED CHROMANES -- 3-NITRO-2-TRIHALOMETHYL-2H-CHROMENES -- CYCLIC NITRONATES Аннотация: 3-Nitro-2-trichloro(trifluoro)methyl-2H-chromenes undergo a formal [4+2] cycloaddition reaction to cyclohexanone and pinacolone enamines, producing chromeno[3,4-c][1,2]benzoxazin-6-oxides with high diastereoselectivity and in good yields. In addition, some novel 2,3,4-trisubstituted chromanes were obtained. The stereochemistry of the products was established based on a 2D NOESY experiment and an X-ray diffraction study \\\\expert2\\nbo\\Tetrahedron\\2014, v. 70 (34), p. 5161.pdf |