Stephen Ley has made extensive contributions to synthetic organic chemistry, embracing both valuable new synthetic methods and the total synthesis of complex macromolecules of biological importance. The former, which grew out of collaboration with Derek Barton, includes the elegant use of organoselenium intermediates in controlled cyclisation reactions, leading to the most efficient synthesis of hirsutene and a novel synthesis of lactones and lactams via tricarbonyliron complexes, including an entirely new route to beta-lactams. This last process has been applied to the ready preparation of several pharmaceutically important compounds. The large number of total syntheses of natural products completed over the last five years include the complex ionophore indamycin X14547A and the insect antifeedants ajugarin I, polygodial and warburganal. Syntheses of azadirachtin, milbemycins and avermectins are well advanced.
Bakerian Medal and Lecture
On 'Sweet dreams: new strategies for oligosaccharide assembly'.
In recognition of his invention of new synthetic methods applied to the synthesis of complex natural products including those from insects, micro-organisms and plants. Among his most outstanding successes have been the synthesis of avermectin B1a, tetrona
For his pioneering research in organic chemistry and outstanding contributions to the methodology of synthesis.