Diastereoselective functionalization of Baylis-Hillman adducts: a convenient approach to alpha-methyl-alpha-amino acids.
The N-tosyl carbamates 4a-e, easily prepared starting from the Baylis-Hillman adducts 3a-e, underwent cyclization carried out with I(2)/NIS in the presence of NaH, to give the corresponding 2-oxo-1,3-oxazolidines 5a-e in good yield and total stereoselection when the substituent at C-5 is Ar. After the removal of tosyl group, followed by the cleavage of the heterocyclic ring, the alpha-methyl-alpha-amino acids 8a,b and 10 were obtained in good yield as hydrochlorides.
Martelli
Gianluca
G
Dipartimento ISAC, Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
Orena
Mario
M
Rinaldi
Samuele
S
Sabatino
Piera
P
D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D023303:Oxazolidinones / Q000138:chemical synthesis; D013237:Stereoisomerism; D014105:Tosyl Compounds / Q000737:chemistry
D000596:Amino Acids; D023303:Oxazolidinones; D014105:Tosyl Compounds