Synthesis of the 2H-quinolizin-2-one scaffold via a stepwise acylation—intramolecular annulation strategy
作者:Swaminathan R. Natarajan、Meng-Hsin Chen、Stephen T. Heller、Robert M. Tynebor、Ellen M. Crawford、Cui Minxiang、Han Kaizheng、Jingchao Dong、Bin Hu、Wu Hao、Shu-Hui Chen
DOI:10.1016/j.tetlet.2006.05.089
日期:2006.7
A rapid entry into the 2H-quinolizin-2-one starting from 2-alkyl pyridine has been developed. Initial deprotonation of a 2-alkyl pyridine followed by acylation with a β-TMS-propyonate derivative provides acyclic precursors that after deprotection undergoes a 6-endo-trig cyclization to yield the desired 2H-quinolizin-2-one derivative. This synthetic strategy was found to be generally applicable as evidenced
Approaches to the Synthesis of (±)-Strychnine via the Cobalt-Mediated [2 + 2 + 2] Cycloaddition: Rapid Assembly of a Classic Framework
作者:Michael J. Eichberg、Rosa L. Dorta、Douglas B. Grotjahn、Kai Lamottke、Martin Schmidt、K. Peter C. Vollhardt
DOI:10.1021/ja016333t
日期:2001.9.1
Five synthetic approaches to racemic strychnine (1), with the cobalt-mediated [2 + 2 + 2] cycloaddition of alkynes to indoles as the key step, are described. These include the generation and attempted cyclization of macrocycle 8 and the synthesis of dihydrocarbazoles 15, 22, and 26 and their elaboration to pentacyclic structures via a conjugate addition, dipolarcycloaddition, and propellane-to-spirofused
Cobalt-mediated [2 + 2 + 2] cycloadditions of alkynes to the indole 2,3-double bond: an extremely facile entry into the novel 4a,9a-dihydro-9H-carbazole nucleus
作者:Douglas B. Grotjahn、K. Peter C. Vollhardt
DOI:10.1021/ja00268a060
日期:1986.4
by the indolenucleus and its presence in a multitude of natural products selective alteration of its structure has commanded a considerable amount of synthetic attention. Part of this effort has involved the utilization of the 2,3-double bond in Diels-Alder and other cycloadditions. The authors report a novel mode of reactivity of this bond in the presence of eta-CpCo reagents: the (2 + 2 + 2) cycloaddition