Unambiguous synthetic routes to sphingofungins B and F and to their stereoisomers have been developed based on the tin(II)-catalyzed asymmetric aldol reaction (Chiral Lewis Acid-Controlled Synthesis (CLAC Synthesis)). Efficient enantioselective synthesis using a catalytic amount of a chiral source as well as the effectiveness of this strategy for the synthesis of the sphingofungin family have been successfully
基于锡 (II) 催化的不对称醛醇反应(手性路易斯酸控制合成(CLAC 合成)),已经开发了鞘氨醇 B 和 F 及其立体异构体的明确合成路线。使用催化量的手性源进行有效的对映选择性合成以及该策略在合成鞘氨醇家族中的有效性已被成功证明。使用合成的鞘氨醇 B 的立体异构体,揭示了其立体化学与其 SPT 抑制活性的相关性。
Selective formation of 1,3,4-trisubstituted and 3,4-disubstituted trans-β-lactams from zinc enolates and imines
作者:Johann T. B. H. Jastrzebski、Fred H. van der Steen、Gerard van Koten
DOI:10.1002/recl.19871060910
日期:——
synthesis (better then 90%) of exclusively trans-β-lactams (azetidin-2-ones) is reported which involves the 1:1 reaction of an α-aminoacid ester zincenolate with an appropriate imine. The reaction can be carried out as a ‘one-pot’ synthesis as has been demonstrated for the synthesis of trans-3-diethylamino-4-phenyl azetidin-2-one (93% yield). The novel zincenolates have most likely a Z-geometry as a result
Diastereofacial selectivity in the reaction of chiral N-trimethylsilyl imines with ester enolates: Preparation of trans-azetidin-2-ones in high stereocontrolled fashion.
Highly efficient chiral ester enolate-imine condensation, giving 3,4-disubstituted β-lactams with excellent trans-syn or trans-anti diastereoselectivity, is reported. The chiral information is included in the electrophilic partner of the condensation, nominally chiral α-, β-silyloxy- or alkoxy-N-trimethylsilyl-imines. The highdiastereofacialselectivity is determined by the correct choice of the metal
据报道,高效手性酯烯酸酯-亚胺缩合可产生具有出色的反式-顺式或反式-非对映体选择性的3,4-二取代的β-内酰胺。手性信息包括在缩合的亲电子伙伴中,名义上为手性α-,β-甲硅烷氧基-或烷氧基-N-三甲基甲硅烷基亚胺。高非对映选择性是由反应介质中存在的金属阳离子的正确选择和羟基保护基团的性质决定的。通过这种方法,已经获得了许多氮杂环丁酮类化合物,它们是合成商业上感兴趣的β-内酰胺类抗生素的中间体。报道了如此获得的氮杂环丁酮的完全归属的1 H和13 C NMR谱。
Meta-containing enolate compounds
申请人:Gist-Brocades N.V.
公开号:US04898955A1
公开(公告)日:1990-02-06
Trans-.beta.-lactams are prepared in a nearly quantitative yield by a condensation reaction of a new intermediate metal enolate and an appropriate imine. Certain new metal enolates are provided as intermediates.
β-Lactams from ester enolates and N-TMSimines: Enantioselective synthesis of (6R, 7S)-1β-3-dimethyl-3-isocephem
作者:Gianfranco Cainelli、Mauro Panunzio、Elisa Bandini、Giorgio Martelli、Giuseppe Spunta、Marco Da Col
DOI:10.1016/0040-4020(95)98703-k
日期:1995.4
lactic aldehyde (4) and cyclic silyl derivative of glycine (2). The elaboration of hydroxyethyl side chain was carried out by functional group interchange (FGI) of the hydroxyl group by a thioacetoxy group, and finally six-membered ring assembly followed by attachment of necessary appendage to N-7 nitrogen atom.