# Synthesis of Quinolizidine-Based 1,4-Azaphosphinines via Cyclization of Heteroarylmethyl(alkynyl)phosphinates

## TL;DR

This paper introduces a new method to create phosphorus-based six-membered rings using a silver-catalyzed reaction, producing novel structures with potential for functional chemistry.

## Contribution

A silver-catalyzed cyclization method for synthesizing previously unreported quinolizidine-based 1,4-azaphosphinine scaffolds.

## Key findings

- The silver-catalyzed cyclization achieves full conversion across over 30 derivatives under mild conditions.
- The method enables the dearomatization of pyridine to form new quinolizidine-based 1,4-azaphosphinine structures.
- The approach expands the structural diversity of phosphorus-containing heterocycles.

## Abstract

Intramolecular hydroarylation
of (phenylethynyl)­phosphinates represents
a powerful strategy for constructing six-membered phosphorus heterocycles.
In this study, we report a silver-catalyzed cyclization protocol that
enables the efficient synthesis of 1,4-aza-phosphorus heterocycles
under mild conditions. The approach demonstrates broad substrate tolerance,
affording full conversion across more than 30 derivatives. Dearomatization
of pyridine leads to the formation of previously unreported quinolizidine-based
1,4-azaphosphinine scaffolds. These novel phosphorus heterocycles
expand the structural diversity of phosphorus-containing frameworks
and open new opportunities in the chemistry of functional heterocycles.