He took his PhD there with Professor A. Albert of the Australian National University – at Euston Road, London.

He collaborated for several years with Professor Donald Holroyde Hey on various aspects of heterocyclic chemistry.

In 1978, he was appointed Hofmann Professor of Organic Chemistry at Imperial College London and remained there until his retirement in 1993.

Rees' research interests ranged widely over mechanistic and synthetic organic chemistry.

Recently, he had been working on heterocyclic systems with unusually high proportions of nitrogen and sulphur heteroatoms.