Catalytic reactions of bis-π-allylpalladium generated from allyltrifluoroborate

Palladium-Catalyzed Dearomative Methoxyallylation of 3-Nitroindoles with Allyl Carbonates

Herein we report a Pd-catalyzed dearomative methoxyallylation of 3-nitroindoles with readily available allyl carbonates. Good yields (up to 86 %) and diastereoselectivity (up to >20:1 dr) are obtained for a wide range of substrates. The compatibility of gram-scale synthesis and the relatively low catalyst loading (down to 1 mol % of [Pd]) enhance the practicality of this method. The kinetic experiments indicate that the rate-determining step of this reaction is the nucleophilic attack of the alkoxide anion.

Merging Pd0 /PdII Redox and PdII /PdII Non-redox Catalytic Cycles for the Allylarylation of Electron-Deficient Alkenes

An allylarylation of electron-deficient alkenes with aryl boronates and allylic carbonates has been developed. This method allows access to a wide variety of carbon skeletons from readily available starting materials. Mechanistic studies indicate that this reaction is enabled by a cooperative catalysis based on merging Pd⁰ /Pd^II redox and Pd^II /Pd^II non-redox catalytic cycles.

Carboallylation of Electron-Deficient Alkenes with Organoboron Compounds and Allylic Carbonates by Cooperative Palladium/Copper Catalysis

The aryl- and alkylallylation of electron-deficient alkenes was achieved by cooperative palladium/copper catalysis. The reaction affords various carbon skeletons from readily available alkenes, allylic carbonates, and organoboron compounds, whereby a variety of functional groups such as acetyl, alkoxycarbonyl, bromo, and cyano moieties are tolerated well.

Computational Study of Enantioselectivity in the Asymmetric Allylation of Aldehydes with Chiral Pt(II) Phosphinite Complexes

Computational investigations on the enantioselectivity observed in the allylation of cinnamaldehyde have been carried out using four closely related chiral platinum catalysts with ascorbic acid-based bisphosphinite ligands. Enantioselectivity depends on the substitution of hydrogen on the hydroxyl group by benzyl group(s) in the ascorbic acid framework. The key intermediate is assumed to be one, where both the aldehyde (via oxygen) and the η¹ allyl group are coordinated to the metal center, and C-C bond formation between the terminal allylic carbon and carbonyl carbon is the rate-determining step. A screening process has been adopted to select potentially relevant reactant adducts from a total of several hundred theoretically possible conformers by molecular mechanics (MM) calculations. Only 50 transition state structures (TSs) lead to the product based on a two-layer QM/MM study employing B3LYP and UFF methods. Out of these 50 TSs, around 10 structures were selected for the final step QM calculation at B3LYP/LANL2TZ(f)(Pt),6-311G(d,p)//B3LYP/LANL2DZ(Pt),6-31G(d,p) level of theory. This computational approach predicts chirality induction correctly in most of the seven catalysts examined. The successful prediction of enantioselectivity carried out using the MM, QM/MM, and QM approaches suggests that the described simplified procedure could be useful in other catalyst systems also.

Amphiphilic π-Allyliridium C,O-Benzoates Enable Regio- and Enantioselective Amination of Branched Allylic Acetates Bearing Linear Alkyl Groups

The first examples of amphiphilic reactivity in the context of enantioselective catalysis are described. Commercially available π-allyliridium C,O-benzoates, which are stable to air, water and SiO2 chromatography, and are well-known to catalyze allyl acetate-mediated carbonyl allylation, are now shown to catalyze highly chemo-, regio- and enantioselective substitutions of branched allylic acetates bearing linear alkyl groups with primary amines.

Carboallylation of electron-deficient alkenes by palladium/copper catalysis

The carboallylation of electron-deficient alkenes with tetraorganosilicon reagents and allylic carbonates has been developed by palladium/copper catalysis.

Allylation of functionalized aldehydes by potassium allyltrifluoroborate catalyzed by 18-crown-6 in aqueous media

An efficient method for the allylation of aldehydes containing a broad range of functional groups using potassium allyltrifluoroborate is described. The reaction utilizes a catalytic amount of 18-C-6 in biphasic media under open atmosphere and room temperature to provide the corresponding homoallylic alcohols in high yields and without the necessity of any subsequent purification.