RESUMO
Herein, we report a highly diastereoselective construction of fused carbocycles using four successive pericyclic reactions.
Assuntos
Alcinos/química , Éteres/química , Compostos Policíclicos/síntese química , Alcinos/efeitos da radiação , Éteres/efeitos da radiação , Micro-Ondas , EstereoisomerismoRESUMO
[reaction: see text] Herein, we present a successful synthesis of the tricyclic core of vinigrol (1). Our approach takes advantage of a highly regioselective intramolecular Diels-Alder reaction of the diene 11 to construct two rings of the tricyclic vinigrol skeleton 12.
Assuntos
Diterpenos/síntese química , Compostos Macrocíclicos/síntese química , Diterpenos/química , Compostos Macrocíclicos/química , Estrutura MolecularRESUMO
Under conventional heat (135-145 degrees C) or microwave irradiation and 1 equiv of acetic anhydride, ortho-substituted aryl-oximes undergo a novel sp3 C-H activated cyclization to produce the corresponding isoindoles, and aliphatic oximes afford the corresponding dihydropyrroles. The cyclization occurs with various substrates in good yield (46-82%) leading to unique spiro-fused and cyclic imines. An initial mechanistic investigation suggests the reaction occurs via a nitrenium or vinyl nitrene intermediate. [reaction: see text]
Assuntos
Técnicas de Química Combinatória , Iminas/síntese química , Oximas/química , Compostos de Espiro/síntese química , Anidridos Acéticos/química , Ciclização , Temperatura Alta , Iminas/química , Indóis/química , Micro-Ondas , Modelos Químicos , Pirróis/química , Compostos de Vinila/químicaRESUMO
We report a gold-catalyzed benzannulation of 3-hydroxy-1,5-enynes to generate tetrahydronaphthalenes. This mild process proves to be an effective method to synthesize various metasubstituted aromatic rings in good yields. [reaction: see text]
Assuntos
Ouro/química , Tetra-Hidronaftalenos/síntese química , Catálise , Ciclização , Indicadores e Reagentes , Isomerismo , Espectroscopia de Ressonância MagnéticaRESUMO
In this article, we report a highly diastereoselective new method for the generation of quaternary carbon centers through an anionic oxy-Cope/alkylation sequence where the diastereoselectivity is induced by the conformation of a macrocyclic tetrasubstituted enolate. The use of our methodology culminated in the formal total synthesis of (-)-mesembrine (34) in 11 steps from known starting materials.