Gold as Catalyst for the Hydroarylation and Domino Hydroarylation/N1–C4 Cleavage of β-Lactam-Tethered Allenyl Indoles
摘要:
Gold-catalyzed hydroarylation reaction of beta-lactam-tethered allenyl indoles gives azeto-oxepino[4,5-b]-indol-2-ones, tetrahydroazeto-azocino[3,4-b]indol-2-ones, and hexahydroazeto-azepino[3,4-b]indol-2-ones with very high levels of stereo, and regioselectivity, the 7-exo and 8-endo carbocyclization modes by attack of the indole group toward either the internal or the terminal allene carbon, respectively, being favored. Hydroarylation across the central carbon of the allene moiety has not been detected. The controlled gold-catalyzed annulations allowed the formation of fused beta-lactams without harming the sensitive four-membered heterocycle. Besides, a novel gold-catalyzed domino process, namely, the allenic hydroarylation/N1-C4 beta-lactam bond breakage to afford dihydro-oxepino[4,5-b]indole-4-carboxamides, has been discovered.
Flow synthesis of organic azides and the multistep synthesis of imines and amines using a new monolithic triphenylphosphine reagent
作者:Catherine J. Smith、Christopher D. Smith、Nikzad Nikbin、Steven V. Ley、Ian R. Baxendale
DOI:10.1039/c0ob00813c
日期:——
Here we describe general flow processes for the synthesis of alkyl and aryl azides, and the development of a new monolithic triphenylphosphine reagent, which provides a convenient format for the use of this versatile reagent in flow. The utility of these new tools was demonstrated by their application to a flow Staudinger aza-Wittig reaction sequence. Finally, a multistep aza-Wittig, reduction and