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Acylammonium salts as dienophiles in Diels-Alder/lactonization organocascades.

ABSTRACT: α,β-Unsaturated acylammonium salts, generated in situ from commodity acid chlorides and a chiral isothiourea organocatalyst, comprise a new and versatile family of chiral dienophiles for the venerable Diels-Alder (DA) cycloaddition. Their reactivity is unveiled through a highly diastereo- and enantioselective Diels-Alder/lactonization organocascade that generates cis- and trans-fused bicyclic γ- and δ-lactones bearing up to four contiguous stereocenters. Moreover, the first examples of DA-initiated, stereodivergent organocascades are described delivering complex scaffolds found in bioactive compounds. The origins of stereoselectivity are rationalized through computational studies. In addition, the utility of this methodology is demonstrated through a concise approach to the core structure of glaciolide and formal syntheses of fraxinellone, trisporic acids, and trisporols.

SUBMITTER: Abbasov ME

PROVIDER: S-EPMC3985498 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature

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Acylammonium salts as dienophiles in Diels-Alder/lactonization organocascades.

Abbasov Mikail E ME Hudson Brandi M BM Tantillo Dean J DJ Romo Daniel D

Journal of the American Chemical Society 20140312 12

α,β-Unsaturated acylammonium salts, generated in situ from commodity acid chlorides and a chiral isothiourea organocatalyst, comprise a new and versatile family of chiral dienophiles for the venerable Diels-Alder (DA) cycloaddition. Their reactivity is unveiled through a highly diastereo- and enantioselective Diels-Alder/lactonization organocascade that generates cis- and trans-fused bicyclic γ- and δ-lactones bearing up to four contiguous stereocenters. Moreover, the first examples of DA-initia ...[more]

PMID: 24588428

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