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在手征分子的合成中,绝对立体化学的控制是个关键问题。形成手征性的一个简捷途径是适当的天然产物的立体化学控制的改造。本文报道一种由容易得到的6-APA(1)立体定向合成一种高效抗生素——硫霉素(Thienamycin)的合成法。转化青霉素的立体化学(5R,6R)为硫霉素的立体化学(5R,6S,8R),得益于β-内酰胺系统对反式取代的高度选择性。因此,用乙酰基置换青霉素6-位上的氮(1→2)并从B 侧还原此螯合的反式酮(2→3),调整其立体化学 C-8和 C-6为 R 和 S 构型。四氢噻唑环
In the synthesis of chiral molecules, absolute stereochemistry control is a key issue. A straightforward way to form chirality is a stereochemical control modification of the proper natural product. In this paper, we report a synthetic method for the synthesis of Thienamycin, a highly effective antibiotic, from stereotactic 6-APA (1). Stereochemistry of penicillin (5R, 6R) is the stereochemistry of (5R, 6S, 8R), which is due to the high selectivity of the β-lactam system for trans-substitution. Therefore, replacement of the nitrogen (1 → 2) at the 6-position of penicillin with an acetyl group and reduction of this chelated trans ketone (2 → 3) from the B side to adjust its stereochemistry C-8 and C-6 to R and S configuration. Tetrahydrothiazole ring