Palladium-catalyzed acetylation of arenes.

A simple method for the preparation of aryl methyl ketones is reported. The transformation involves the Pd-catalyzed coupling of an acyl anion equivalent, acetyltrimethylsilane, with aryl bromides to afford the corresponding acetylated arenes in synthetically useful yields. The methodology is tolerant of heterocycles and provides a new method for arene functionalization

Amino Amide Organocatalysts for Asymmetric Michael Addition of β-Keto Esters with β-Nitroolefins

Asymmetric Michael addition of β-keto esters with trans-β-nitroolefins using chiral amino amide organocatalyst was tried and afforded synthetically useful chiral Michael adducts in both excellent chemical yields (up to 99%) and stereoselectivities (up to dr. 99:1, up to 98% ee)

Development of a simple system for the oxidation of electron-rich diazo compounds to ketones

Mild heating of diazo compounds in DMSO furnishes ketone products in moderate to excellent yields. The reaction is particularly effective on electron-rich substrates and exhibits high chemoselectivity, allowing for the use of diazo compounds containing additional oxidation-prone functional groups. This straightforward protocol offers an alternate route to synthetically useful ɑ-ketoesters from readily available aryl diazoacetates

Attractive aerobic access to the α,β-unsaturated acyl azolium intermediate: oxidative NHC catalysis via multistep electron transfer

To replace high molecular weight oxidants with air (O2) we introduce multistep electron transfer NHC catalysis. The method provides a general and selective oxidation of the α,β-unsaturated aldehyde derived homoenolate to the synthetically useful α,β-unsaturated acyl azolium intermediate. Several independent oxidative NHC-catalyzed reactions are viable with this strategy and the products can be isolated in high to excellent yields

Nickel-catalyzed transamidation of aliphatic amide derivatives.

Transamidation, or the conversion of one amide to another, is a long-standing challenge in organic synthesis. Although notable progress has been made in the transamidation of primary amides, the transamidation of secondary amides has remained underdeveloped, especially when considering aliphatic substrates. Herein, we report a two-step approach to achieve the transamidation of secondary aliphatic amides, which relies on non-precious metal catalysis. The method involves initial Boc-functionalization of secondary amide substrates to weaken the amide C-N bond. Subsequent treatment with a nickel catalyst, in the presence of an appropriate amine coupling partner, then delivers the net transamidated products. The transformation proceeds in synthetically useful yields across a range of substrates. A series of competition experiments delineate selectivity patterns that should influence future synthetic design. Moreover, the transamidation of Boc-activated secondary amide derivatives bearing epimerizable stereocenters underscores the mildness and synthetic utility of this methodology. This study provides the most general solution to the classic problem of secondary amide transamidation reported to date

Electrochemical Ruthenium‐Catalysed Directed C−H Functionalization of Arenes with Boron Reagents

Ortho-directed electrochemical C−H functionalization of aromatics with boron-based coupling partners has been achieved under ruthenium catalysis through an oxidatively induced reductive elimination mechanism. Our method provides a single set of conditions delivering C−H arylation, alkenylation and methylation, yielding ortho-functionalized products with good functional group tolerance, including examples of late-stage functionalization in synthetically useful yields. By harnessing electricity as a ‘green’ oxidant, this method circumvents the need for stoichiometric quantities of chemical oxidants, enhancing our sustainability metrics

Tandem ring-closing metathesis reaction with a ruthenium catalyst containing a N-heterocyclic ligand

The highly active catalyst 2 was used in tandem RCM to make molecules with various ring systems containing α,β-unsaturated carbonyl compounds

Rapid Assembly of the Salvileucalin B Norcaradiene Core

Preparation of the polycyclic core of the cytotoxic natural product salvileucalin B is described. The key feature of this synthetic strategy is a copper-catalyzed intramolecular arene cyclopropanation to provide the central norcaradiene. These studies lay the foundation for continued investigations toward an enantioselective total synthesis of 1

Amine catalysis for the organocatalytic diboration of challenging alkenes

© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The generation of in situ sp 2 –sp 3 diboron adducts has revolutionised the synthesis of organoboranes. Organocatalytic diboration reactions have represented a milestone in terms of unpredictable reactivity of these adducts. However, current methodologies have limitations in terms of substrate scope, selectivity and functional group tolerance. Here a new methodology based on the use of simple amines as catalyst is reported. This methodology provides a completely selective transformation overcoming current substrate scope and functional/protecting group limitations. Mechanistic studies have been included in this report