Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

• Xiu-Yu Chen,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

• reaction with 5,6-unsubstituted 1,4-dihydropyridine. Keywords: [3 + 2] cycloaddition; cyclopenta-1,3-diene; cyclopenta[4,5]pyrrolo[2,3-b]pyridine; 1,4-dihydropyridine; electron-deficient alkyne; isocyanide; Introduction Isocyanide is a unique and attractive functional group in organic chemistry. The

• intermediate B. Thirdly, the intramolecular coupling of the positive charge and the negative charge in intermediate B resulted in the formation of polysubstituted 5-(alkylimino)cyclopenta-1,3-diene intermediate C, which has been described in several papers about the reaction of alkyl isocyanides and electron

• -deficient alkynes [59][60][61][62][63]. The in situ generated cyclic intermediate C has a resonance hybrid C’. Then, the further nucleophilic addition of the electron-rich enamino unit to 5-(alkylimino)cyclopenta-1,3-diene intermediate C gave intermediate D. At last, the coupling of the iminium cation with

The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• mixture of 24/25, following the procedure given by Le Goff [13], proceeded as expected and provided the potassium salt of 28 in acceptable yields (60%). From this, free 1,2,3,4,5-pentakis(methoxycarbonyl)cyclopenta-1,3-diene 28 was liberated by hydrochloric acid treatment in excellent yield (>90%, Scheme

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• cycloadditions proceeded with complete regio- and stereoselectivity with respect to the olefin 1, but less so with respect to the ketene 3 (Table 1), such that endo-4 and exo-4 isomers were formed in variable amounts, depending on the nature of the substrates. In general, the conversions of cyclopenta-1,3-diene