Stereochemical alchemy! Racemic allyl β-ketoesters allow the regiocontrolled formation of enolates, where the same catalyst is intimately involved in both the stereoablative (C-C bond-breaking) and stereoselective (C-C bond-forming) steps. This mechanistic and practical insight led to the formation of multiple quaternary carbon stereocenters in a single cascade reaction (see scheme).

Deracemization of Quaternary Stereocenters by Pd‐Catalyzed Enantioconvergent Decarboxylative Allylation of Racemic β‐Ketoesters

Arylation with organolead and organobismuth reagents

Enantioselective tandem michael reaction to nitroalkene catalyzed by bifunctional thiourea : total synthesis of (-)-epibatidine

Isoflavonoids and related compounds

Palladium-catalyzed intramolecular α-arylation of aliphatic ketone, formyl, and nitro groups

Arylation of A- ring substituted and unsubstituted 3-allyloxycarbonylchroman-4-ones with aryllead (IV) triacetates followed by selective catalytic deallyloxycarbonylation affords isoflavanones or isoflavones in high overall yields. The highest yield in the arylation step was observed in the reaction of 5,7-dimethoxychroman-4-one with the more hindered 2,4,6-trimethoxyphenyllead triacetate.

Organolead-mediated arylation of allyl β-ketoesters: a selective synthesis of isoflavanones and isoflavones

Arylation of the A-ring-unsubstituted and -substituted 3-(allyloxycarbonyl)chroman-4-ones 6–8 with [4,5-dimethoxy-2-(methoxymethoxy)phenyl]lead(IV) triacetate 5 followed by selective catalytic deallyloxycarbonylation–dehydrogenation afforded 2′-protected isoflavones in high overall yields. Acid-catalysed removal of the methoxymethyl group led to the corresponding 2′-hydroxyisoflavones.

Bernard A. Rattigan

Papers

Organolead-mediated arylation of allyl β-ketoesters: a selective synthesis of isoflavanones and isoflavones

Organolead-mediated arylation of allyl β-keto esters: selective synthesis of 2′-hydroxyisoflavones

Organolead-Mediated Arylation of Allyl β-Keto Esters: Selective Synthesis of 2′-Hydroxyisoflavones.

Organolead-Mediated Arylation of Allyl β-Ketoesters: A Selective Synthesis of Isoflavanones and Isoflavones.