RESUMO
Synthesis of the tetracyclic cores of madangamines D-F was achieved, featuring a reductive radical process from an ethoxycarbonyldichloroacetamide to build the morphan nucleus, a Mitsunobu-type aminocyclization toward the common diazatricyclic intermediate, and ring-closing metathesis reactions for the macrocyclization step leading to the 13- to 15-membered rings.
Assuntos
Alcaloides/síntese química , Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Alcaloides/química , Ciclização , Compostos Heterocíclicos de 4 ou mais Anéis/química , Biologia Marinha , Estrutura Molecular , EstereoisomerismoRESUMO
Intramolecular Kharasch-type additions of trichloroacetamides on anisole and enol acetates catalyzed by Grubbs' ruthenium carbenes are described. This protocol provides access to highly functionalized 2-azaspiro[4.5]decanes, morphan compounds, and the azatricyclic core of FR901483.
RESUMO
An enantioselective approach to (-)-isoavenaciolide was achieved starting from 1-undecyn-3-ol. The synthesis relied upon the preparation of a chiral 4-silyloxy-2-alkenylborane by hydroboration of a protected 2,3-allenol and subsequent stereoselective addition to 2-thiophenecarboxaldehyde.
Assuntos
4-Butirolactona/análogos & derivados , 4-Butirolactona/síntese química , 4-Butirolactona/química , Boranos/química , Estrutura Molecular , Estereoisomerismo , Tiofenos/químicaRESUMO
A novel synthetic entry to 2-azabicyclo[3.3.1]nonanes based on a copper(I)-catalyzed intramolecular coupling of amino-tethered trichloroacetamides and unsaturated nitriles, esters and alkenes, as well as enol acetates, is described. A study of the reaction conditions and the scope of the process is reported.