# Oligomerisation and stereoselective polymerisation of alkenes and alkynes using pyridyl-based Al(iii) catalysts

## TL;DR

Scientists created new aluminum-based catalysts that can efficiently polymerize alkenes and cyclotrimerize alkynes with high stereocontrol.

## Contribution

This is the first report of stereoselective Al(iii) polymerization and alkyne cyclotrimerization using static main group metal catalysis.

## Key findings

- The Al(iii) cationic catalysts polymerize alkenes with high stereoregularity, including syndiotactic polystyrene.
- The catalysts cyclotrimerize terminal alkynes to form trisubstituted benzenes and fulvene.

## Abstract

Dealkylation of the dimers [R2Al(2-py′)]2 (2-py′ = 6-substituted pyridyl, R = Me, iBu) with [Ph3C][B(C6F5)4] gives the putative cations [RAl(2-py′)2(µ-R)AlR]+ which can polymerise a range of alkenes with a high degree of stereoregularity (syndiotacticity in the case of polystyrene) and which cylotrimerise terminal alkynes to trisubstituted benzenes and a fulvene. This is the first report of stereoslective Al(iii) polymerisation and of the cyclotrimerisation of alkynes by static catalysis using a main group metal.

The putative Al(iii) cationic catalysts [RAl(2-py′)2(µ-R)AlR]+ (2-py′ = 6-substituted pyridyl, R = Me, iBu) can polymerise terminal alkenes with a high degree of stereocontrol and cyclotrimerise terminal alkynes.