Development of a Merged Conjugate Addition/Oxidative Coupling Sequence. Application to the Enantioselective Total Synthesis of Metacycloprodigiosin and Prodigiosin R1
journal contributionposted on 14.10.2009, 00:00 by Michael D. Clift, Regan J. Thomson
A merged conjugate addition/oxidative coupling sequence that represents an efficient strategy for preparing structurally diverse pyrroles has been developed. Success of the method hinged upon the controlled oxidative coupling of unsymmetrical silyl bis-enol ether intermediates, formed by the 1,4-addition of a Grignard reagent with subsequent enolate trapping by a (chloro)silylenol ether. The process was applied to the first enantioselective syntheses of the biologically active pyrrolophane natural products, metacycloprodigiosin and prodigiosin R1.