# Exploring the Reactivity of Rigid 1-Azadienes Derived from Methylene γ-Lactams. Applications to the Stereoselective Synthesis of Spiro-γ-Lactams

## TL;DR

This paper explores how rigid 1-azadienes from methylene γ-lactams can be used to create spiro-γ-lactams with high stereospecificity.

## Contribution

The first example of using methylene-γ-lactams to synthesize spirocycles with four stereogenic centers is presented.

## Key findings

- Rigid 1-azadienes can act as both diene and dienophile in cyclodimerization.
- Chiral rigid 1-azadienes enable stereospecific synthesis of spiro-γ-lactams.
- A multicomponent reaction efficiently produces the starting 1-amino α,β-unsaturated γ-lactam derivatives.

## Abstract

A study on the reactivity
of rigid 1-azadienes derived from methylene
γ-lactams is reported. Through the functionalization of 1-amino
α,β-unsaturated γ-lactam derivatives, easily available
from a multicomponent reaction of amines, aldehydes, and pyruvates,
it is possible to in situ generate rigid 1-azadienes locked by a γ-lactam
core. The 4π-electron system of those rigid 1-azadienes can
behave as both diene and dienophile species through a spontaneous
cyclodimerization reaction or exclusively as dienes or dienophiles
if they are trapped with imines or cyclopentadiene, respectively.
The use of chiral rigid 1-azadienes as dienophiles in the cycloaddition
reaction with cyclopentadiene leads to the formation of spiro-γ-lactams
bearing four stereogenic centers in a highly stereospecific manner,
reporting the first example of the use of methylene-γ-lactams
in the synthesis of spirocycles.