Regio- and Diastereoselective Synthesis of Dihydropyridopyrimidines via Cascade Reactions of 2‑Aminopyridines with Morita–Baylis–Hillman Bromides of Nitroalkenes

The Morita–Baylis–Hillman (MBH) bromides of nitroalkenes have been employed as bielectrophiles for the first time. The 1,3-bielectrophilic reactivity of the MBH bromides has been demonstrated in the synthesis of 3,4-dihydro-2<i>H</i>-pyrido­[1,2-<i>a</i>]­pyrimidines. The reaction of MBH bromides with 2-aminopyridines takes place in the absence of any reagent in a cascade S_N2′-6-endo-trig fashion and is completely regioselective and highly stereoselective. The products, in their hydrobromide salt form, could be conveniently isolated and purified by crystallization. The high stereoselectivity has been rationalized in terms of the greater stability of the transition state in which the Ar and NO₂ groups are anti to each other

Regio- and Diastereoselective Synthesis of Dihydropyridopyrimidines via Cascade Reactions of 2‑Aminopyridines with Morita–Baylis–Hillman Bromides of Nitroalkenes

The Morita–Baylis–Hillman (MBH) bromides of nitroalkenes have been employed as bielectrophiles for the first time. The 1,3-bielectrophilic reactivity of the MBH bromides has been demonstrated in the synthesis of 3,4-dihydro-2<i>H</i>-pyrido­[1,2-<i>a</i>]­pyrimidines. The reaction of MBH bromides with 2-aminopyridines takes place in the absence of any reagent in a cascade S_N2′-6-endo-trig fashion and is completely regioselective and highly stereoselective. The products, in their hydrobromide salt form, could be conveniently isolated and purified by crystallization. The high stereoselectivity has been rationalized in terms of the greater stability of the transition state in which the Ar and NO₂ groups are anti to each other

(3 + 3) Annulation of Nitroallylic Acetates with Stabilized Sulfur Ylides for the Synthesis of 2‑Aryl Terephthalates

A novel (3 + 3) annulation approach has been developed for the synthesis of 2-aryl terephthalates from nitroallylic acetates and stabilized sulfur ylides. The 2-aryl terephthalates, which are also biaryls bearing a terephthalate moiety, are formed through a cascade of reactions such as a γ-selective S_N2′ reaction, γ-selective intramolecular Michael addition, and two eliminations in the presence of Cs₂CO₃ in CH₃CN at room temperature. The products are formal precursors of farnesyltransferase inhibitors and are also potential monomers in polymer chemistry

(3 + 3) Annulation of Nitroallylic Acetates with Stabilized Sulfur Ylides for the Synthesis of 2‑Aryl Terephthalates

A novel (3 + 3) annulation approach has been developed for the synthesis of 2-aryl terephthalates from nitroallylic acetates and stabilized sulfur ylides. The 2-aryl terephthalates, which are also biaryls bearing a terephthalate moiety, are formed through a cascade of reactions such as a γ-selective S_N2′ reaction, γ-selective intramolecular Michael addition, and two eliminations in the presence of Cs₂CO₃ in CH₃CN at room temperature. The products are formal precursors of farnesyltransferase inhibitors and are also potential monomers in polymer chemistry

One-Pot Construction of Functionalized Spiro-dihydronaphthoquinone-oxindoles via Hauser–Kraus Annulation of Sulfonylphthalide with 3‑Alkylideneoxindoles

The Hauser–Kraus annulation of sulfonylphthalide with 3-olefinic oxindole has been performed. This strategy, which involves a cascade Michael addition–Dieckmann cyclization–elimination sequence, offers rapid and convenient access to novel spiro-dihydronaphthoquinone-oxindoles in excellent yields with complete selectivity for the enolic form under mild reaction conditions