Ring closing metathesis in organic synthesis: Evolution of a high speed, solid phase method for the preparation of β-turn mimetics

Abstract

Complimentary solid phase syntheses of the Freidinger lactam class of β-turn mimetics have been developed using ring closing metathesis as both the key carbon-carbon bond forming step and the cyclative cleavage mechanism. Solid phase variants of the Fukuyama-Mitsunobu process were utilized as part of a rapid three-step sequence to construct immobilized lactam precursors. An alternative solid phase process is offered which utilizes an Ugi/ring closing metathesis reaction tandem to deliver the desired compounds in two synthetic operations.