Diastereoselective Route to Piperidine and Indolizidine Scaffolds From Enantiopure Vinylsulfinyl-Containing Amino Alcohols
摘要:
A new route to functionalized piperidine and indolizidine scaffolds, based on the diastereoselective intramolecular Michael cyclization of vinyl-sulfinyl-containing amino alcohols 1-3, has been developed. Pyrolytic elimination of the resulting cycloadducts resulted in the regioselective formation of the corresponding tetrahydropyridines and indolizidines. The observed regiochemical course of this process can be explained mainly in terms of the steric bias imposed by the disposition of the arylsulfinyl group and the concerted syn mechanism accepted for this kind of elimination.
An optimized procedure for the diastereoselectiveallylation under aqueous Barbier conditions of a series of alpha-amino aldehydes with our new chiral building block (S(s))-3-chloro-2-(p-tolylsulfinyl)-1-propene [(S(s))-1a] to afford enantiomerically pure sulfinylamino alcohols in good yields and diastereoselectivites is reported. High levels of diastereoinduction can be achieved from alpha-amino aldehydes
A new route to functionalized piperidine and indolizidine scaffolds, based on the diastereoselective intramolecular Michael cyclization of vinyl-sulfinyl-containing amino alcohols 1-3, has been developed. Pyrolytic elimination of the resulting cycloadducts resulted in the regioselective formation of the corresponding tetrahydropyridines and indolizidines. The observed regiochemical course of this process can be explained mainly in terms of the steric bias imposed by the disposition of the arylsulfinyl group and the concerted syn mechanism accepted for this kind of elimination.