RESUMO
A stereocontrolled approach to the cis-decalin framework of clerodane diterpenes and biologically active quinone sesquiterpenes is reported. Starting from an inexpensive optically pure tetrahydroindanone, Birch reductive alkylation builds two new contiguous chiral centers-one of which is quaternary and all-carbon-substituted. Also featured is a highly regioselective diazoalkane-carbonyl homologation reaction to prepare the 6,6-bicyclic skeleton. Therein, the utility of Sc(OTf)3 as a mild catalyst for formal 1C insertion in complex settings is demonstrated.
Assuntos
Diterpenos Clerodânicos/química , Quinonas/síntese química , Sesquiterpenos/síntese química , Catálise , Modelos Químicos , Estrutura Molecular , Quinonas/química , Sesquiterpenos/química , EstereoisomerismoRESUMO
In contrast to high spin pyridyl diimine iron(ii) dichloride complexes, analogous bis(amidinato)-N-heterocyclic carbene iron(ii) and iron(iii) complexes demonstrate complex magnetic behaviour. In the solid state, they are best described as intermediate spin complexes at low temperatures that demonstrate gradual spin transitions beginning near or below room temperature. Treating the bis(amidinato)-N-heterocyclic carbene iron(ii) complex with an aryl azide revealed enhanced reactivity compared to analogous complexes supported by pyridyl diimine ligands.
RESUMO
An efficient and operationally simple approach to complex cis-hexahydroindanes is reported. Upon Birch reduction of unprotected, C4-alkylated tetrahydroindanols and electrophilic trapping of the tetrasubstituted enolate, cis-fused products are formed with a new stereogenic quaternary carbon. The reaction is convergent, completely diastereoselective, and shows a broad scope with regard to the electrophile.