Scandium-catalyzed preparation of cytotoxic 3-functionalized quinolin-2-ones: Regioselective ring enlargement of isatins or imino isatins
Trimethylsilyldiazomethane in the presence of catalytic amounts of Sc(OTf) 3 smoothly promotes the ring expansion of isatins or imino isatins to efficiently afford 3-functionalized quinolin-2-ones through controlled ring enlargement. Whereas the ring-expansion reaction of azetidine-2,3-diones led to the adduct resulting from migration of the carbonyl group, the ring-expansion reaction of oxindole derivatives gave the adduct resulting from migration of the aryl group. To rationalize the experimental observations, theoretical studies have been performed. Moreover, the biological activity of some of the synthesized heterocycles has been evaluated in four cancer cell lines. © 2012 Wiley-VCH Ver…
Ring Expansion versus Cyclization in 4-Oxoazetidine-2- carbaldehydes Catalyzed by Molecular Iodine: Experimental and Theoretical Study in Concert
13 páginas, 3 figuras, 12 esquemas, 2 tablas.-- El documento en word es el articulo post-print.
Controlled rearrangement of lactam-tethered allenols with brominating reagents: a combined experimental and theoretical study on α- versus β-keto lactam formation.
N-Bromosuccinimide (NBS) smoothly promotes the ring expansion of lactam-tethered allenols to efficiently afford cyclic α- or β-ketoamides with good yields and high chemo-, regio-, and diastereoselectivity, through controlled C-C bond cleavage of the β- or γ-lactam nucleus. Interestingly, in contrast to the rearrangement reactions of 2-azetidinone-tethered allenols, which lead to the corresponding tetramic acid derivatives (β-keto lactam adducts) as the sole products, the reactions of 2-indolinone-tethered allenols under similar conditions give quinoline-2,3-diones (α-keto lactam adducts) as the exclusive or major products. To rationalize the experimental observations, theoretical studies ha…