A novel enantiopure phenyl isocyanide (1) carrying l-proline derivative was designed and synthesized. Living polymerization of 1 using a alkyne-Pd(II) catalyst affording a series of helical poly-1_ms with controlled molecular weights (M_ns) and narrow molecular weight distributions (M_w/M_ns) bearing l-proline ester as the pendants. Removed the protecting groups on the l-proline pendants lead to the formation of helical poly-1_m-A. Very interestingly, the left-handed backbone of poly-1_m was reversed to right-handed helix in poly-1_m-A as revealed by circular dichroism (CD) and polarimetry. Optically active helical poly-1_m-A showed excellent catalytic ability on asymmetric aldol reaction. Comparing to the small molecule (1-A) with similar structure, both the enantioselectivity and the diastereoselectivity of the aldol reaction were significantly enhanced. The enantiomeric excess (ee) and diastereomeric ratio (dr) values of the aldol reaction are up to 95% and >20/1, respectively. Moreover, the helical polyisocyanides catalyst can be easily recovered and reused in the aldol reaction at least four cycles without significant loss of its enantioselectivity and diastereoselectivity.

中文翻译：

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带有脯氨酸侧链的螺旋多异氰酸酯对有机催化不对称醛醇缩合反应的对映选择性和非对映选择性的显着提高

设计并合成了一种新型的带有1-脯氨酸衍生物的对映体纯的苯基异氰酸酯（1）。使用炔烃-Pd（II）催化剂进行1的活性聚合，得到一系列螺旋聚1 _m s，具有受控的分子量（M _n s）和窄分子量分布（M _w / M _n s），带有l-脯氨酸酯作为吊坠。除去在保护基升-脯氨酸吊坠导致螺旋聚的形成1_米-A。非常有趣的是，poly- 1 _m的左手骨干圆二色性（CD）和旋光法显示，在多1 _m -A中，“ α”反转为右旋螺旋。旋光螺旋聚1 _m -A对不对称的羟醛反应显示出优异的催化能力。与具有相似结构的小分子（1- A）相比，醛醇缩合反应的对映选择性和非对映选择性均得到显着提高。对映体过量（ee）和非对映体比率（dr）羟醛反应的值分别高达95％和> 20/1。此外，螺旋多异氰酸酯催化剂可以容易地回收并在醛醇缩合反应中至少重复四个循环，而不会显着损失其对映选择性和非对映选择性。