Synthesis of optically active spiro-β-lactams by cycloadditions to α-alkylidene-β-lactams
作者:Sven Anklam、Jürgen Liebscher
DOI:10.1016/s0040-4020(98)00296-8
日期:1998.6
11-E and 11-Z were synthesized and submitted to 1,3-dipolar cycloadditions with diazomethane, 4-methoxybenzonitrile oxide, and diphenylnitrone as well as to epoxidation by dimethyldioxirane. All cycloadditions proceed with complete regioselectivity giving products 20 – 25 in an anti-fashion with respect to the substituent at the C-4-position of the starting β-lactam in diastereomeric ratios of about 80:20
合成了新的旋光性α-亚甲基-β-内酰胺18和α-亚乙基-β-内酰胺11-E和11-Z,并使其与重氮甲烷,4-甲氧基苄腈和二苯基硝酮一起进行1,3-偶极环加成反应关于二甲基二环氧乙烷的环氧化。所有的环加成反应都具有完全的区域选择性,相对于起始β-内酰胺C-4位的取代基,非对映体比例为80:20,这使产品20-25处于反时尚状态。色谱后几乎在所有情况下都可以得到纯的光学活性化合物。可以通过X射线晶体分析和NOE研究来明确结构。