Novel Methods for the construction of Biologically Active Natural Products based on a chiron-synthetic strategy

我们最近报道了一种新颖的、立体的方法，用于从鞑靼酸、糖和谷氨酸作为chiral pool的构造中提炼的同源乳actam衍生物，and demonsrtated the possibility for the biologically active alkaloids In employing这些化合物的总合成的可能性，在这次会议上，我们希望有两个结果，即立体声选择性的路线到有效和间接地纯五溴化蛋白质已经被开发出来。by using reductive deoxygenation and/or stereoselective reduction of quaternary-hydroxy N-Boc pyrrolidine derivatives prepared from alkylation of the functionalized homochiral lactams。在更晚的情况下，确切地说，它可能通过对H-D1-Y-D1的碳基功能的预先攻击从其顶部的六成员金属失调比五成员的一个due对三个大型功能组的屏蔽效应进行描述。最后，一个有效和立体声的过程被描述为第一个不对称合成的四聚氰胺生物碱， broussonetine C，作为一种含有β-半乳糖苷酶和β-半乳糖苷酶抑制剂，通过这种立体质素还原方法来表征的利用。

We have recently reported novel and stereoselective methods for the construction of homochiral lactam derivatives elaborated from tartaric acid, sugar, and glutamic acid as a chiral pool, and demonsrtated the possibility for the total synthesis of biologically active alkaloids employing these compouds.In this conection we wish to communicate two results that a stereoselective route to enantiomerically and diastereomerically pure pentasubstituted pyrrolidines has been developed by using reductive deoxygenation and/or stereoselective reduction of quaternary α-hydroxy N-Boc pyrrolidine derivatives prepared from alkylation of the functionalized homochiral lactams. In the latter case, especially, it could proceed through the predominant attack of HィイD1-ィエD1 on the carbonyl function from the top face of the six-membered metal-chalate rather than five-membered one due to the shielding effect of the three large functional groups.Finally, an efficient and stereodefined process was described for the first asymmetric synthesis of a tetrasubstituted pyrrolidine alkaloid, broussonetine C, as a potent β-galactosidase and β-mannosidase inhibitor by featuring the elaboration through this stereoselective reduction method.