Catalytic <i>Syn</i>-Selective Nitroaldol Approach to Amphenicol Antibiotics: Evolution of a Unified Asymmetric Synthesis of (−)-Chloramphenicol, (−)-Azidamphenicol, (+)-Thiamphenicol, and (+)-Florfenicol
diastereo- and enantioselective synthesis of (−)-chloramphenicol, (−)-azidamphenicol, (+)-thiamphenicol, and (+)-florfenicol based on a key catalytic syn-selective Henryreaction is reported. The stereochemistry of the ligand-enabled copper(II)-catalyzed aryl aldehyde Henryreaction of nitroethanol was first explored to forge a challenging syn-2-amino-1,3-diol structure unit with vicinal stereocenters
报告了基于关键催化顺选择性亨利反应高效和高非对映选择性和对映选择性合成 (-)-氯霉素、(-)-阿齐丹苯、(+)-噻吩苯胺和 (+)-氟苯尼考的统一策略. 首次探索了配体启用的铜 (II) 催化的硝基乙醇的芳醛亨利反应的立体化学,以形成具有挑战性的合成-2-氨基-1,3-二醇结构单元,具有具有出色立体控制的邻位立体中心。进行了多步连续流动操作以实现该家族的双酚类抗生素的有效不对称合成。
Recoverable PEG-supported amino alcohol ligand for copper-catalyzed Enantio- and syn-selective henry reaction with nitroethanol: Sustainable and straightforward access to chiral syn-2-nitro-1,3-Diols
A poly(ethylene glycol) (PEG) supported amino alcohol has been developed as a chiral ligand to promote the copper-catalyzed asymmetric nitrolaldol reaction (Henry Reaction) with nitroethanol. The catalyst provides direct access to various syn-2-nitro-1,3-diols with high yields and stereoselectivities. The solubility of PEG moiety allows facile purification and recycling of the catalyst. The utility