RESUMO
A facile and diversity-oriented synthetic strategy toward aminocyclitol natural products from inexpensive C2-symmetric l-tartaric acid was developed. The pivotal epoxide was used as a common intermediate to accomplish eight diverse target molecules in six to eleven steps. Various allyl-amine-type conduramines were synthesized in a diastereoselective manner. Heck arylation was explored to construct a phenanthridone ring in a concise synthesis of (+)-lycoricidine. In addition, a highly efficient formal synthesis of (-)-laminitol was developed.
Assuntos
Alcaloides de Amaryllidaceae/síntese química , Aminas/síntese química , Cicloexenos/síntese química , Inositol/análogos & derivados , Fenantridinas/síntese química , Fenóis/síntese química , Alcaloides de Amaryllidaceae/química , Aminas/química , Cicloexenos/química , Inositol/síntese química , Inositol/química , Estrutura Molecular , Fenantridinas/química , Fenóis/química , EstereoisomerismoRESUMO
We have prepared [2]rotaxanes, the behavior of which as switchable catalysts depends on their pirouetting motion, which can be controlled through the addition and removal of Na+ ions. At least three sequential on/off cycles of a Michael reaction can be performed in situ when using the NaTFPB/[2.2.2]cryptand reagent pair to switch "on" and "off" the catalytic ability of the [2]rotaxanes.
RESUMO
Size-complementary cyclotriveratrylene (CTV)-based hosts can incarcerate C76 , C78 , and C84 , thus allowing the selective isolation of these higher-order fullerenes from a commercially available mixture of fullerenes. The hemicarceplexes, formed after the encapsulation of the size-complementary fullerenes within the hosts, are isolated by column chromatography and released at elevated temperature, thereby leading to the isolation of C76 /C78 and C84 in good purities (up to 95 and 88 %, respectively).