A diastereospecific synthesis of α-amino-β- hydroxycyclohexenecarboxylic acid (7) was found starting from 4- chloromethylene-5(4H)-oxazolone (1) which reacted with 2,3-dimethylbutadiene in the presence of EtAlCl2. The Diels-Alder reaction gave two diastereoisomeric cycloadducts 2 and 3, depending on the configuration of the starting dienophile 1. Compounds 2a and 3 were transformed into the ester 4 and the oxazoline 6, respectively, by reaction with MeOH and p-TSA. The reaction of 2a and 3 with dimethylamine in ethanol solution gave the corresponding amides 8 and 9, respectively, which were transformed into the bicyclic oxazoline 10 on reaction with Na2CO3 in acetonitrile. On acidic hydrolysis both oxazolines 6 and 10 were transformed into α-amino-β- hydroxycyclohexenecarboxylic acid (7) that includes the serine skeleton.
|Titolo:||A highly diastereoselective approach to conformationally constrained serine analogues: Synthesis of an α-amino-β-hydroxycyclohexenecarboxylic acid and derivatives|
CLERICI, FRANCESCA (Primo)
GELMI, MARIA LUISA (Secondo)
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||1999|
|Digital Object Identifier (DOI):||10.1021/jo9821877|
|Appare nelle tipologie:||01 - Articolo su periodico|