Biomimetic Enantioselective Total Synthesis of (-)-Siccanin via the Pd-Catalyzed Asymmetric Allylic Alkylation (AAA) and Sequential Radical Cyclizations

J. Am. Chem. Soc., 126 (39), 12565 -12579, 2004. 10.1021/ja048084p S0002-7863(04)08084-9
Web Release Date: September 3, 2004

Biomimetic Enantioselective Total Synthesis of (-)-Siccanin via the Pd-Catalyzed Asymmetric Allylic Alkylation (AAA) and Sequential Radical Cyclizations

Barry M. Trost,* Hong C. Shen, and Jean-Philippe Surivet

Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080

bmtrost@stanford.edu

Received April 2, 2004

Abstract:

(-)-Siccanin (1), a natural product possessing significant antifungal properties, was synthesized enantioselectively via a biomimetic route. This synthetic route features two sequential radical cyclizations: a Ti(III)-mediated radical cyclization of epoxyolefin 48 to construct the B-ring, and a Suarez reaction to establish the tetrahyrofuran ring. Chiral chroman moiety of siccanin was prepared based on our recent development of the Pd-catalyzed asymmetric allylic alkylation (AAA) of phenol trisubstituted allyl carbonates. Several other members of the siccanin family were also synthesized including siccanochromenes A (2), B (3), E (6), F (7), and the methyl ether of siccanochromene C (55). These studies may shed light on the biosynthesis of this novel family of compounds.

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