Gilman Speeter reaction

GilmanSpeeter reaction. The Gilman-Speeter reaction is the coupling of anion enolates with imines (Scheme 2). 

Solid-Phase Synthesis of (3-Lactam by Gilman-Speeter Reaction. 287... 

The ester enolate-imine condensation, also called Gilman-Speeter reaction, is another well-accepted method for (3-lactam synthesis (Scheme 4) [67-69]. In 1997, Tomioka reported the first example of a direct catalytic enantioselective synthesis of (3-lactam by using this method [70]. The active reagent is a ternary complex (comprising LDA, the ester enolate, and tridentate amino diether), which finally affords the (3-lactam compounds in high yields and good ee values. 

Scheme 4 Gilman-Speeter reaction in P-lactam synthesis...

Solid-Phase Synthesis of P-Lactam hy Gilman-Speeter Reaction... 

This reaction is related to the Gilman-Speeter Reaction and Staudinger Cycloaddition. 

This reaction was first reported by Gilman and Speeter in 1943. It is an efficient preparation of 3-alkyl-substituted or unsubstituted j8-lactams by the condensation of a Reformatsky reagent and an imine. Therefore, this reaction is generally known as the Gilman-Speeter reaction or Gilman-Speeter condensation. In addition, the extended reactions between lithium ester enolate or lithium thioester enolate and imine are also considered as the Gilman-Speeter reaction. 

It was found that ultrasound can facilitate the reaction and increase the yields of p-lactams. s However, the Gilman-Speeter reaction has not yet been extensively explored, probably due to the slow reaction rate and relatively low yields that usually appear at 20-50%.2 ... 

The Gilman-Speeter reaction involves the formation of a Reformatsky reagent from Qf-haloester, nucleophilic addition of the Reformatsky reagent to an imine, and subsequent intramolecular cyclization to form jS-lactam, as displayed below. 

The modifications of the Gilman-Speeter reaction include the activation of zinc by tri-methylsilyl chloride (TMSCl) and the application of lithium ester enolate" or lithium thioester enolate as the substitute for the traditional Reformatsky reagent. In these modifications, it was found that TMSCl-activated zinc is much more effective in promoting the reaction between ethyl bromoacetate and Schiff bases. In addition, in the presence of a chiral ether ligand, the reaction between lithium ester enolate and imines affords 0-lactams of high enantiomeric excess, probably due to the formation of a ternary complex reagent. " The enantioselectivity and reactivity of the ternary complex depend on the size and nature of the lithium amide used. For example, the lithium amide from 2,2,6,6-tetramethylpiperidine (LTMP) is unfavorable for this reaction." ... 

Other references related to the Gilman-Speeter reaction are cited in the literature. ... 

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