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以Ｌ－抗坏血酸（１）为原料， 经３ 步反应制得（Ｓ）－缩异丙氧叉甘油醛（４）． 该手性醛与苄胺缩合制得相应的手性亚胺（５）． 甘氨酸经保护后制成酰氯， 在有机碱作用下首先生成不稳定的烯酮（８）， 继与手性亚胺５ 迅速进行［２＋ ２］环加成反应， 合成标题化合物Ｎ－苄基－３（Ｓ）－邻苯二甲酰亚胺基－４（Ｓ）－［４（Ｓ）－２，２－二甲基－１，３－二氧环戊－４－基］－２－氧吖丁啶． 由于环加成的面向立体选择性容易控制， 由此所得产物的光学纯度和化学收率均较高
L-Ascorbic acid (1) was used as the starting material to obtain (S) -isopropyloxisoglyceraldehyde (4) via 3 steps. The condensation of the chiral aldehyde with benzylamine gives the corresponding chiral imine (5). Glycine is protected to form an acid chloride. First, an unstable ketene (8) is generated under the action of an organic base and the [2+ 2] cycloaddition reaction with chiral imine 5 proceeds rapidly to synthesize the title compound N-benzyl- Phthalimido-4 (S) - [4 (S) -2,2-dimethyl-1,3-dioxolan-4- Azetidine. Due to the stereoselectivity of the cycloaddition is easily controlled, the optical purity and chemical yield of the resulting product are both high