Dipartimento ISAC, Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
Amino Acids. 2010 Jul;39(2):489-97. doi: 10.1007/s00726-009-0465-y. Epub 2010 Mar 6.
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.
N-对甲苯磺酰基氨基甲酸酯 4a-e 可由 Baylis-Hillman 加成物 3a-e 轻松制备，在碘化亚铜/碘化钠 (I(2)/NIS) 和氢化钠存在下进行环化反应，得到相应的 2-氧代-1,3-恶唑烷 5a-e，产率高，且当 C-5 上的取代基为芳基时具有立体选择性。对甲苯磺酰基被脱去后，杂环被裂解，得到盐酸盐形式的 α-甲基-α-氨基酸 8a,b 和 10，产率高。
