During his four year stay he helped create short direct routes to cortisone,[4] and to all of the major sex hormones.
He set up a strong team and “reverted to his old love, acetylene chemistry, as the basis for his most original and fundamental contribution, the chemistry of the annulenes.”[1][6] In 1963 he accepted, and then rejected, the offer of a prestigious professorship at the University of Chicago, accepting instead one of the newly created Royal Society Research Professorships at the University of Cambridge.
[1] His membership citation read: Professor Sondheimer is distinguished for his work on the total synthesis of a range of natural products, the partial synthesis of steroid hormones and analogues, and especially for his syntheses of the hitherto unknown class of conjugated unsaturated macrocyclic compounds which has led to some interesting theoretical conclusions.
[7] However, funding problems, the difficulty of recruiting foreign postdoctoral students, and his continued focus on now-unfashionable areas of research, all contributed to this not being a satisfactory chapter in his career.
[8] Sondheimer's notable students include K. C. Nicolaou, Raphael Mechoulam, Timothy Walsgrove, and Henry N. C. Wong.