Pd-Catalyzed Enantioselective Dearomative Allylic Annulation to Access PPAPs Analogues
Polycyclic polyprenylated acylphloroglucinols (PPAPs) share a common bicyclo[3.3.1]alkenone core structure and attract numerous attention from synthetic organic chemists due to their fascinating biological properties and associated synthetic challenges. We present herein that Pd-phosphoramidite catalysts promote the enantioselective dearomative allylic annulation reaction between allyl desoxyhumulones and allylic dicarbonates, affording PPAPs analogues in good yields and enantioselectivities. The reaction likely proceeds through two-step dearomative allylation by Pd, and the C-allylation pathway is the dominant mechanistic model.
Asymmetric Dearomatization/Cyclization Enables Access to Polycyclic Chemotypes
Enantioenriched, polycyclic compounds were obtained from a simple acylphloroglucinol scaffold. Highly enantioselective dearomatization was accomplished using a Trost ligand–palladium(0) complex. A computational DFT model was developed to rationalize observed enantioselectivities and revealed a key reactant-ligand hydrogen bonding interaction. Dearomatized products were used in visible light-mediated photocycloadditions and oxidative free radical cyclizations to obtain novel polycyclic chemotypes including tricyclo[4.3.1.01,4]decan-10-ones, bicyclo[3.2.1]octan-8-ones and highly substituted cycloheptanones.
Hayashi, Mikayo,Brown, Lauren E.,Porco, John A.
p. 4800 - 4804
(2016/10/13)
Asymmetric, stereodivergent synthesis of (-)-clusianone utilizing a biomimetic cationic cyclization
We report a stereodivergent, asymmetric total synthesis of (-)-clusianone in six steps from commercial materials. We implement a challenging cationic cyclization forging a bond between two sterically encumbered quaternary carbon atoms. Mechanistic studies point to the unique ability of formic acid to mediate the cyclization forming the clusianone framework. Aim for selectivity: (-)-Clusianone was produced by a stereodivergent asymmetric total synthesis in six steps from commercial materials. The synthesis utilizes a challenging formic acid-mediated cationic cyclization forging a bond between two sterically encumbered quaternary carbon atoms.
Boyce, Jonathan H.,Porco, John A.
supporting information
p. 7832 - 7837
(2014/08/05)
Rapid synthesis of polyprenylated acylphloroglucinol analogs via dearomative conjunctive allylic annulation
Polyprenylated acylphloroglucinols (PPAPs) are structurally complex natural products with promising biological activities. Herein, we present a biosynthesis-inspired, diversity-oriented synthesis approach for rapid construction of PPAP analogs via double decarboxylative allylation (DcA) of acylphloroglucinol scaffolds to access allyl-desoxyhumulones followed by dearomative conjunctive allylic alkylation (DCAA).
Grenning, Alexander J.,Boyce, Jonathan H.,Porco, John A.
p. 11799 - 11804
(2014/10/16)
Manganese(III)-mediated transformations of phloroglucinols: A formal oxidative [4 + 2] cycloaddition leading to bicyclo[2.2.2]octadiones
Manganese(III)-mediated oxidative transformations of dearomatized phloroglucinol (1,3,5-trihydroxybenzene) derivatives are reported. A number of cyclization modes have been observed, including polycyclization to afford bicyclo[2.2.2]octadiones via a forma
Mitasev, Branko,Porco Jr., John A.
supporting information; experimental part
p. 2285 - 2288
(2009/11/30)
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