Ley's main research field are the
total synthesis of
biomolecules. His group has published extensively on this topic, and has completed the synthesis of more than 140 natural target compounds, with notable examples including indanamycin, routiennocin, avermectin B1a, okadaic acid, spongistatin,
thapsigargin,
epothilone A, antascomicin B, bengazole A and
rapamycin. His total synthesis of
azadirachtin, completed in 2007, is widely regarded as one of the major landmarks in total synthesis. In the course of this work, he has also made substantial advances in many areas of organic chemistry, including the development of new
catalysts,
protecting groups and
reagents. He is one of the inventors of
TPAP, a widely employed oxidising reagent. He has also pioneered the use of immobilised reagents and flow techniques in multi-step organic synthesis. This work now incorporates
flow chemistry for multistep organic synthesis applications. By 2020, Ley had published 888 academic research papers spanning his career of 50 years. ==Honours and awards==