Practical, Broadly Applicable, α-Selective, Z-Selective, Diastereoselective, and Enantioselective Addition of Allylboron Compounds to Mono-, Di-, Tri-, and Polyfluoroalkyl Ketones.

A practical method for enantioselective synthesis of fluoroalkyl-substituted Z-homoallylic tertiary alcohols has been developed. Reactions may be performed with ketones containing a polylfluoro-, trifluoro-, difluoro-, and monofluoroalkyl group along with an aryl, a heteroaryl, an alkenyl, an alkynyl, or an alkyl substituent. Readily accessible unsaturated organoboron compounds serve as reagents.

Role of sterically demanding chiral dirhodium catalysts in site-selective C-H functionalization of activated primary C-H bonds.

The influence of sterically demanding dirhodium tetracarboxylate catalysts on the site selectivity of C-H functionalization by means of rhodium carbene-induced C-H insertion is described. The established dirhodium tetraprolinate-catalyzed reactions of aryldiazoacetates cause preferential C-H functionalization of secondary C-H bonds as a result of competing steric and electronic effects. The sterically more demanding dirhodium tetrakis(triarylcyclopropanecarboxylate) catalysts, exemplified by dirhodium tetrakis[(R)-(1-(biphenyl)-2,2-diphenylcyclopropanecarboxylate)] [Rh2(R-BPCP)4], favor C-H functionalization of activated primary C-H bonds.

Guide to Enantioselective Dirhodium(II)-Catalyzed Cyclopropanation with Aryldiazoacetates.

Catalytic enantioselective methods for the generation of cyclopropanes has been of longstanding pharmaceutical interest. Chiral dirhodium(II) catalysts prove to be an effective means for the generation of diverse cyclopropane libraries. Rh(-DOSP) is generaally the most effective catalyst for asymmetric intermolecular cyclopropanation of methyl aryldiazoacetates with styrene.

Silver-catalyzed vinylogous fluorination of vinyl diazoacetates.

A silver-catalyzed vinylogous fluorination of vinyl diazoacetates to generate γ-fluoro-α,β-unsaturated carbonyls is presented. Application of this method to the fluorination of farnesol and steroid derivatives was achieved.

Rh2(R-TPCP)4-catalyzed enantioselective [3+2]-cycloaddition between nitrones and vinyldiazoacetates.

Rhodium-catalyzed reaction of vinyldiazoacetates with nitrones results in a formal [3+2]-cycloaddition to generate 2,5-dihydroisoxazoles with high levels of asymmetric induction. The cascade reaction begins with a vinylogous addition event, followed by an iminium addition ring-closure/hydride migration/alkene isomerization cascade. Dirhodium tetrakis(triarylcyclopropanecarboxylates) are the optimum catalysts for this process.

Enantioselective synthesis of 2-arylbicyclo[1.1.0]butane carboxylates.

The rhodium-catalyzed reaction of 2-diazo-5-arylpent-4-enoates can be controlled by the appropriate choice of catalyst and catalyst loading to form either 2-arylbicyclo[1.1.0]butane carboxylates or cyclohexene derivatives.

D2-symmetric dirhodium catalyst derived from a 1,2,2-triarylcyclopropanecarboxylate ligand: design, synthesis and application.

Dirhodium tetrakis-(R)-(1-(4-bromophenyl)-2,2-diphenylcyclopropanecarboxylate) (Rh(2)(R-BTPCP)(4)) was found to be an effective chiral catalyst for enantioselective reactions of aryl- and styryldiazoacetates. Highly enantioselective cyclopropanations, tandem cyclopropanation/Cope rearrangements and a combined C-H functionalization/Cope rearrangement were achieved using Rh(2)(R-BTPCP)(4) as catalyst. The advantages of Rh(2)(R-BTPCP)(4) include its ease of synthesis, its tolerance to the size of the ester group in the styryldiazoacetates, and its compatibility with dichloromethane as solvent.

Palladium-catalyzed aromatic esterification of aldehydes with organoboronic acids and molecular oxygen.

A palladium-catalyzed aromatic esterification reaction of aldehydes with arylboronic acids under an air atmosphere was achieved. This reaction tolerates many functional groups and provides aryl benzoate derivatives with yields ranging from moderate to good. Dioxygen takes part in the reaction and is crucial for this transformation.

The palladium-catalyzed addition of aryl- and heteroarylboronic acids to aldehydes.

Reaction of aryl- or heteroarylboronic acids with aldehydes, in the presence of PdCl2 and P(1-Nap)3, afforded carbinol derivatives in good to excellent yields. The efficiency of this reaction was demonstrated by the compatibility with nitro, cyano, acetamido, acetoxy, acetyl, carboxyl, trifluoromethyl, fluoro, and chloro groups and the possibility of involving aliphatic aldehyde or hindered substrates. Moreover, the rigorous exclusion of air/moisture is not required in these transformations.