Vinoth Perumal, Vivekanand Thavaraj, Suryavanshi Padmakar A, Menéndez J Carlos, Sasai Hiroaki, Sridharan Vellaisamy
Organic Synthesis Group, Department of Chemistry, School of Chemical and Biotechnology, SASTRA University, Thanjavur 613401, Tamil Nadu, India.
Org Biomol Chem. 2015 May 14;13(18):5175-81. doi: 10.1039/c5ob00458f.
A catalytic, atom-economical, domino 5-endo-dig cyclization-intramolecular olefin insertion sequence was developed under mild conditions. Aryl alkynoic acids bearing a tethered enone partner afforded the indeno[1,2-b]furan-2-ones, the core skeleton present in a number of biologically significant molecules including the natural product solanacol, under ligand-free, palladium-catalyzed reaction conditions in high yields. The competitive β-hydride elimination in the final step leading to the conjugated analogs was avoided by the addition of lithium bromide. A plausible mechanism for this domino sequence is proposed involving intramolecular carboxypalladation and olefin insertion steps.
在温和条件下开发了一种催化、原子经济的多米诺5-内型-环化-分子内烯烃插入序列。带有连接烯酮的芳基炔酸在无配体、钯催化的反应条件下，高产率地得到了茚并[1,2-b]呋喃-2-酮，这是许多具有生物学意义的分子（包括天然产物茄那醇）中的核心骨架。通过加入溴化锂避免了在最后一步导致共轭类似物的竞争性β-氢消除。提出了一种合理的多米诺序列机理，涉及分子内羧基钯化和烯烃插入步骤。
