# The Facile Synthesis of Exogenous Lewis-Base-Free Amidoalanes: A Structural Comparison

## TL;DR

This paper describes a simple method to synthesize stable amidoalane compounds and compares their structures.

## Contribution

A new one-pot synthesis method for exogenous Lewis-base-free amidoalanes is introduced.

## Key findings

- Amidoalanes are formed as crystalline solids with yields between 35–85%.
- Seven X-ray structures show most amidoalanes exist as dimers, except one trimer.
- These compounds are stable enough to be briefly handled in air.

## Abstract

A simple one-pot reaction of LiAlH4, AlCl3, and a secondary amine HNR2 [R = Et, iPr, iBu, cyclo-C6H11, (CH2)4, and (CH2)5] in hydrocarbon solvents results in the formation of exogenous Lewis-base-free amidoalanes [H2Al(NR2)]n (n = 2 or 3) as crystalline solids (35–85% yield). In the solid state (seven X-ray structures), all the amidoalanes exist as dimers, with the exception of the pyrrolidine-derived alane which exists as a trimer. As solids, these amidoalanes exhibit significant kinetic stability towards oxygen/moisture allowing the brief (ca. 5 min.) handling of [H2Al(NiPr2)]2 in air.