Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
J Org Chem. 2013 Apr 19;78(8):3647-54. doi: 10.1021/jo400164y. Epub 2013 Apr 5.
Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee's up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary.
高对映体富集的γ-和δ-内酰胺可以通过一种简单且非常有效的方法制备，该方法涉及 N-（叔丁基亚磺酰基）亚氨基酯的不对称转移氢化，随后在碱性后处理过程中脱去氮原子上的磺酰基并自发环化生成所需的内酰胺。带有芳香族、杂芳香族和脂肪族取代基的五元和六元环内酰胺以非常高的收率和高达 >99%的 ee 值获得。该方法的稍加修改也允许以良好的收率和非常高的对映选择性制备ε-内酰胺。通过改变手性亚磺酰基的绝对构型，可以以相同的效率制备最终内酰胺的两种对映体。
