Lactams p-, synthesis

Spirocyclic p-Lactams Synthesis and Biological Evaluation of Novel Heterocycles... 

Scheme 73 P-Lactams synthesis via photochemical rearrangement of a-oxoamides...

Scheme 74 /ram-Substituted P-lactams synthesis by photochemically induced Staudinger reaction... 

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

Alhylation (Acyl Species -> a-Alhylated Acyl Product) An efficient procedure for the C(a)-re alkylation of lithium and sodium enolates of Af-acylsultams with various (even nonacti-vated) primary halides in the presence of HMPA has been developed (88.7-99% de). Alkylation with ClCH2NMeC02Bn enables a two-step p-lactam synthesis. Michael-type alkylation... 

As a Chiral Starting Material in p-Lactam Synthesis. Various p-lactams have been prepared via [2 + 2] cyclization of ket-enes with aryl or benzyl imines derived from the reagent. Thus the para-methoxyphenyl imine derived from condensation of the corresponding aniline and the reagent underwent [2 + 2] cycloadditions with various ketenes to afford p-lactams in moderate yields but with very high stereoselectivity (eq 14). ... 

A p-Lactam Synthesis Via a Deep Rooted Dislocation of the Starting Material... 

P-Lactams, synthesis by photochemical pericyclic reactions 86YGK1058. 

Baldwin, J.E., Adhngton, R.M., Russell, A.T., and Smith, M.L., Carbon based nucleophilic ring opening of activated monocyclic P-lactams. Synthesis and stereochemical assignment of the ACE inhibitor WE-10129. Tetrahedron, 51, 4733, 1995. 

This reaction can also be applied to P-lactam synthesis as depicted below. Treatment of the p-K-allylcarbonyliron intermediate with benzylamine followed by oxidation by cerium(IV) yields the P-lactam framework in high yield (Scheme 10.7) [22]. 

The allyl group was used to protect the nitrogen in a P-lactam synthesis, hut was removed in a four-step sequence. ... 

Duguet N, Campbell CD, Slawin AMZ, Smith AD (2008) N-heterocyclic carbene catalysed P-lactam synthesis. Org Biomol Chem 6 1108-1113... 

Many methods have been developed for p-lactam synthesis, including cyclisation of the corresponding amino acids. The most widely used methods are two-component couplings, which occur via concerted cycloaddition or two-step mechanisms. Another simple route to 3-functionalised azetidinones is the reaction of aziridine-2-carboxylic acid sodium salt with oxalyl chloride or thionyl chloride. ... 

Iron chiral auxiliary for asymmetric aldol reaction, Michael addition, p-amino acid and p-lactam synthesis. 

Condensation reactions of simple carboxylic acids with imines are of intense interest because of their applications to p-lactam synthesis. Activation of the carboxylic acid derivative is accomplished by preforming the enolate in situ or by using a silyl ketene acetal derivative with Lewis acid catalysis. The first example of an enolate-imine condensation of this type can be attributed to Gillman and Speeter, who in 1943 reported the synthesis of P-lactams from Reformatsky reagents and Schiff bases.87 Subsequently, other workers have investigated the mechanism and syn-anti selectivity of this reaction. A review of these studies by Evans et al. covering work through 1980 has appeared in their review, Stereoselective Aldol Condensations .10... 

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