The Synthesis of a Degradation Product of Phomazarin: A Regiospecific Elaboration of the B and C Rings of the Pigment
作者:Vincent Guay、Paul Brassard
DOI:10.1055/s-1987-27924
日期:——
An attempt to confirm the structure proposed for phomazarin has been initiated by the synthesis of one of its degradation products. The methods chosen also resulted in the regiospecific elaboration of the B and C rings of the pigment and are applicable to eventual syntheses by convergent approaches.
strategy activated the C-Br bonds of α-bromo-alkylcarboxylic esters to provide carbon-centered radicals under the catalysis of Ir(iii) photocatalyst and coupled with indole derivatives. This methodology displayed wide functional group tolerance and excellent regioselectivity, and was applied to the late-stage functionalization and preparation of indole-containing hybrids.
2-(3-indolyl)ethylamine (3) and (S)-(N)-(l-p-menthen-8-yl)-2-(3-indolyl)ethylideneamine (4). The latter has been transformed into (−)-hobartine (6) in 64% yield via a stereoselective biomimetic cyclization by treatment with HCOOH. This unambiguous synthesis establishes the hitherto unknown absolute configuration of (−)-hobartin (6). Several model cyclization reactions of N-substituted α-(terpen-8-yl)imine
Esters and amides from aziridine 2-carboxylic acid salts
作者:C. Lambert、H.G. Viehe
DOI:10.1016/s0040-4039(00)88924-8
日期:1985.1
Potassium salts of aziridine-2-carboxylic acid derivatives are efficiently converted into esters of amides by reactions with alkyl halides, alkyl dihalides or by acylation with trimethylacetyl chloride followed by aminolyses.
Copper(II)-Catalyzed [4+1] Annulation of Propargylamines with<i>N</i>,<i>O</i>-Acetals: Entry to the Synthesis of Polysubstituted Pyrrole Derivatives
作者:Norio Sakai、Hiroaki Hori、Yohei Ogiwara
DOI:10.1002/ejoc.201500098
日期:2015.3
Described herein is the CuCl2-catalyzed [4+1] annulation of a variety of propargylamines with N,O-acetals that function as a C1 unit, leading to the production of polysubstitutedpyrrolederivatives. Three important features of the N,O-acetal during the [4+1] annulation series via 5-endo-dig cyclization are described: an enolizable substituent adjacent to the central sp3-carbon is required, the central