Intramolecular cyclization of N-allyl propiolamides: a facile synthetic route to highly substituted γ-lactams (a review)

Abstract

The development of simple and efficient methods for construction of substituted γ-lactams is an important synthetic goal because such ring skeletons are present in numerous natural compounds that display diverse biological activities.

Diastereoselective C–H carbonylative annulation of aliphatic amines: a rapid route to functionalized γ-lactams

“… 1 Among these scaffolds, 2-pyrrolidinones represent a synthetically versatile class of heterocycle due to the diverse reactivity imparted by the amide functional group. The majority of transformations that generate the 2-pyrrolidinone scaffold can be mainly divided into two reaction classifications: cyclization of bifunctional substrates 2 – 5 and transformations of appropriately functionalized 5-membered ring core. 6 Of particular importance to the successful realization of these processes is the need for reactive functional groups resident within the framework of the precursors to the nitrogen heterocycle.…”

The reaction of a particularly electrophilic acyclic diaminocarbene with carbon monoxide: formation of β- and γ-lactams

“…The βlactams are one of the best known and intensively investigated ring systems due to both their utility as synthetic intermediates and their biological activity as antibiotics [31][32][33]. In the same vein, γ-lactams are at the heart of a number of medicinally and biologically important compounds, as well as a large collection of natural products, and the synthesis of functionalised γ-lactams is therefore attracting increased attention [34,35]. Very recently, a palladium-catalysed route to functionalised γ-lactams Scheme 1: Plausible formation mechanism for the lactams formed by carbonylation of in situ-generated iPr 2 N-C-TMP.…”

Divergent and Diastereoselective Synthesis of α-Monosubstituted and trans-α,β-Disubstituted γ-Lactams from (S)-N,N-Dibenzyl-α-amino Aldehydes via Henry and Michael Reactions

“…Representative natural products and pharmaceutical compounds containing -lactam moiety Due to the great diversity of biological activities and structural complexity, there is an expressive number of different synthetic approaches in the literature for obtaining natural and synthetic -lactams. Some selected approaches include four-component reaction (4CR) between amines, maleic anhydride, aldehydes, and thiols, 8 intramolecular cyclization of N-allylpropiolamides, 9 expansion or contraction of a previously formed ring, 10,11 sp 3 and sp 2 C-H amidation 12…”

“…In turn, the trans-,-disubstituted -lactam 11, could be synthesized from nitroester derivative 10b, via a domino reduction-cyclization process. 43 Already 10b,c could be formed via a diastereoselective anti-Michael addition of dimethyl malonate (9) to chiral nitroalkenes 8b,c, under the action of different basic catalysts. The Michael acceptors 8b,c have been synthesized from N,N-dibenzylated aldehydes 6b,c by a concise and efficient route developed by us 31 (Scheme 1, Route 3).…”