PHOSPHINE-CATALYZED [3 + 2] ANNULATION: SYNTHESIS OF ETHYL 5-(tert-BUTYL)-2-PHENYL-1-TOSYL-3-PYRROLINE-3-CARBOXYLATE

Described herein is a catalytic asymmetric total synthesis of (−)-actinophyllic acid, with the key step being a chiral phosphine-catalyzed [3 + 2] annulation between an imine and an allenoate to form a pyrroline intermediate in 99% yield and 94% ee. The synthesis also features CuI-catalyzed coupling between a ketoester and a 2-iodoindole to shape the tetrahydroazocine ring; intramolecular alkylative lactonization; SmI2-mediated intramolecular pinacol coupling between ketone and lactone subunits to assemble the complex skeleton of (−)-actinophyllic acid; and an unprecedented regioselective dehydroxylation.

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Phosphine-catalyzed intramolecular γ-umpolung addition of α-aminoalkylallenic esters: facile synthesis of 3-carbethoxy-2-alkyl-3-pyrrolines

Andrews¹,

Blank²,

Kwon³

2012

Chem. Commun.

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An array of N-tosylated α-aminoalkylallenic esters was prepared and their cyclization under the influence of nucleophilic phosphine catalysts was explored. The α-aminoalkylallenic esters were prepared through aza-Baylis–Hillman reactions or novel DABCO-mediated decarboxylative rearrangements of allenylic carbamates. Conversion of these substrates to 3-carbethoxy-2-alkyl-3-pyrrolines was facilitated through Ph3P-catalyzed intramolecular γ-umpolung addition.

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PHOSPHINE-CATALYZED [3 + 2] ANNULATION: SYNTHESIS OF ETHYL 5-(tert-BUTYL)-2-PHENYL-1-TOSYL-3-PYRROLINE-3-CARBOXYLATE

Cited by 8 publications

References 5 publications

Catalytic C–C Bond Forming Reaction to Imines

Catalytic C–C Bond Forming Reaction to Imines

Catalytic Asymmetric Total Synthesis of (−)-Actinophyllic Acid

Phosphine-catalyzed intramolecular γ-umpolung addition of α-aminoalkylallenic esters: facile synthesis of 3-carbethoxy-2-alkyl-3-pyrrolines

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