S 98 Synthesis of 8-R-9c-alkyl-1-aryl-2-benzyl-1-hydroxy-1,2,9b,9c-tetrahydro-5-oxa-2-aza-cyclopenta[2,3]cyclopropa[1,2-a]naphthalene-3,4-diones and reaction thereof with acetic anhydride [Text] / V. V. Shchepin, P. S. Silaichev, A. R. Racitin, M. I. Kodess // Tetrahedron Letters. - 2006. - Vol. 47, № 4. - P557-560 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The reaction of zinc enolates synthesized from 1-aryl-2,2-dibromoalkanones and zinc with 6-R-2-oxochromene-3-carboxylic acid N-benzylamide affords 8-R-9c-alkyl-1-aryl-2-benzyl-1-hydroxy-1,2,9b,9c-tetrahydro-5-oxa-2-aza-cyclopenta[2,3]cyclopropa[1,2-a]naphthalene-3,4-diones. Acylation of these compounds is accompanied by an unexpected rearrangement producing a sole geometrical isomer of 4?-alkyl-5?-aryl-1?-benzyl-3,4,2?,3?-tetrahydro-2,2?-dioxospiro[chroman-3,3?-pyrrol]-4-yl acetates \\\\Expert2\\nbo\\Tetrahedron Letters\\2006, v. 47, p.557.pdf |