Assuntos
Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Rodófitas/química , Esqualeno/análogos & derivados , Esqualeno/química , Compostos Heterocíclicos de 4 ou mais Anéis/química , Conformação Molecular , Estrutura Molecular , Esqualeno/síntese química , Estereoisomerismo , Terpenos/química , Terpenos/isolamento & purificaçãoRESUMO
The asymmetric synthesis of tetraol (+)-3, a degradation product derived from a C2 symmetric oxasqualenoid intricatetraol 1, has been achieved through the two-directional synthesis starting from diol 7, realizing the further additional assignment of the incomplete stereostructure of 1, the stereochemistry of which is difficult to determine otherwise.
Assuntos
Esqualeno/análogos & derivados , Esqualeno/química , Álcoois/síntese química , Álcoois/química , Compostos de Epóxi/síntese química , Compostos de Epóxi/química , Modelos Moleculares , Conformação Molecular , Esqualeno/síntese químicaRESUMO
The plane structure and partial stereochemistry of a cytotoxic bromotriterpene polyether (+)-aurilol (1), isolated from the sea hare Dolabella auricularia, were mainly elucidated by NMR methods; however, determination of the entire stereochemistry has not been reached. Although there have also been many other types of triterpene polyethers, it is often difficult to determine their stereostructures even by the current highly advanced spectroscopic methods, especially in acyclic systems including quaternary carbon centers such as C10-C11, C14-C15, and C18-C19 in 1. In this paper, we report that the total assignment of the incomplete stereostructure of (+)-aurilol (1) to the structural formula 2 has been accomplished through its first asymmetric total synthesis featuring the highly regio- and stereocontrolled biogenetic-like A-D ether ring formations.
Assuntos
Éteres Cíclicos/síntese química , Terpenos/síntese química , Triterpenos/síntese química , Animais , Aplysia/química , Éteres/síntese química , Éteres/química , Hidrocarbonetos Bromados/síntese química , Hidrocarbonetos Bromados/química , Estereoisomerismo , Terpenos/químicaRESUMO
The unknown stereostructure of 2-amino-3-cyclopropylbutanoic acid 1, a novel plant growth regulator isolated from the mushroom Amanita castanopsidis Hongo, was determined to be (2S,3S)-2 through its racemic and enantioselective syntheses employing the chelate-enolate Claisen rearrangement as a key step.