Discovery of novel sulfonamide derivatives containing pinacolone moieties as fungicide candidates against Botrytis cinerea.

Background: Botrytis cinerea is one of the most serious plant diseases and severely threatens agricultural production. The rapidly intensifying resistance makes most commercial chemical fungicides lose control efficacy. Developing new fungicides with novel structures and modes of action is an effective measure to solve this problem.

Asymmetric hydrogenation of exocyclic γ,δ-unsaturated β-ketoesters to functionalized chiral allylic alcohols dynamic kinetic resolution.

An iridium catalyzed asymmetric hydrogenation of racemic exocyclic γ,δ-unsaturated β-ketoesters dynamic kinetic resolution to functionalized chiral allylic alcohols was developed. With the chiral spiro iridium catalysts Ir-SpiroPAP, a series of racemic exocyclic γ,δ-unsaturated β-ketoesters bearing a five-, six-, or seven-membered ring were hydrogenated to the corresponding functionalized chiral allylic alcohols in high yields with good to excellent enantioselectivities (87 to >99% ee) and -selectivities (93 : 7 to >99 : 1). The origin of the excellent stereoselectivity was also rationalized by density functional theory calculations.

Enantioselective Total Syntheses of Pentacyclic Homoproaporphine Alkaloids.

Herein we report the first enantioselective total syntheses of pentacyclic homoproaporphine alkaloids by means of a route, which includes a tandem retro-oxa-Michael addition and nucleophilic substitution to generate the oxa-benzobicyclco[3.3.1]nonane core structure, a Pictet-Spengler cyclization to construct the fused B and C rings, and sequential Baeyer-Villiger oxidation and pinacol-type cyclization to install the hydroxyl-lactol moiety of D ring.

Iridium-Catalyzed Asymmetric Hydrogenation of γ- and δ-Ketoacids for Enantioselective Synthesis of γ- and δ-Lactones.

A highly efficient asymmetric hydrogenation of γ- and δ-ketoacids was developed by using a chiral spiro iridium catalyst ()-, affording the optically active γ- and δ-hydroxy acids/lactones in high yields with excellent enantioselectivities (up to >99% ee) and turnover numbers (TON up to 100000). This protocol provides an efficient and practical method for enantioselective synthesis of Ezetimibe.

Scalable Enantioselective Total Synthesis of (-)-Goniomitine.

A scalable enantioselective total synthesis of (-)-goniomitine has been developed by using an iridium-catalyzed asymmetric hydrogenation of an exocyclic enone ester to control the configuration of the molecule. The synthesis begins from commercially available starting materials, and proceeds through an integrated asymmetric ketone hydrogenation, Johnson-Claisen rearrangement, and one-pot oxidation/deprotection/cyclization process. With this highly efficient and scalable strategy, (-)-goniomitine was synthesized in eleven steps with 27 % overall yield, and formal enantioselective syntheses of (+)-1,2-dehydroaspidospermidine, (+)-aspidospermidine, and (+)-vincadifformine were also achieved.