A novel pyrrole synthesis

Abstract

The silver(I)-promoted oxidative cyclization of homopropargylamines at room temperature provides a novel access to pyrroles. Homopropargylamines are readily available by the addition of a propargyl Grignard reagent to Schiff bases.

Harmicine, a Tetracyclic Tetrahydro-β-Carboline: From the First Synthetic Precedent to Isolation from Natural Sources to Target-Oriented Synthesis (Review)*

“…They describe the utilization of their newly developed silver(I)-promoted pyrrole synthesis from homopropargylamines [57]. Nucleophilic addition of Grignard reagent 36 to the preformed BF 3 salt of 3,4-dihydro-β-carboline 37 [58], prepared by a two-step procedure involving the Bischler-Napieralski reaction [59][60][61], starting from tryptamine (4) and ethyl formate, gave THβC 38 (Scheme 14).…”

Total synthesis of biologically active alkaloids using transition metals

“…Therefore, besides the classical Hantzsch, Knorr, and Paal-Knorr synthesis, many alter native routes to this heterocyclic framework have been described. Recently, we have developed a novel synthesis of pyrroles by a simple three-component coupling and subsequent Ag(I)-mediated cyclization [69].…”

Transition metals in organic synthesis, Part 105. Synthesis of pyrroles by silver(I)-promoted oxidative cyclization

“…3,4 In 2004, we described a novel synthesis of pyrroles based on a threecomponent coupling followed by a silver(I)-promoted oxidative cyclization of the resulting homopropargylamines. 5 Our silver(I)-promoted oxidative cyclization of homopropargylamines was applied to the total synthesis of natural products containing annulated pyrroles, 6 like the indolizino [8,7-b]indole alkaloid (±)-harmicine and the pyrrolo [2,1-a]isoquinoline alkaloid (±)-crispine A. 7,8 In the present paper, we report full details of the silver(I)-promoted oxidative cyclization to 1,2-diarylpyrroles.…”