Sarah J Ryan

• Monash University (Australia)

Reaction discovery using N-heterocyclic carbene organocatalysis has been dominated by the chemistry of acyl anion equivalents. Recent studies demonstrate that NHCs are far more diverse catalysts, with a variety of reactions discovered that proceed without acyl anion equivalent formation. In this tutorial review selected examples of acyl anion free...

Lewis base catalysed 1,3-dipolar cycloaddition between α,β-unsaturated acyl fluorides and N-[(trimethylsilyl)methyl]amino ethers has been achieved using 1 mol% DMAP. Competition experiments and (19)F-NMR studies indicate that the cycloaddition occurs preferentially between the α,β-unsaturated acyl fluoride and the unstabilised azomethine ylide. In...

NHCs activate a diverse range of materials and thereby play a central role in modern reaction discovery. Our studies have focused on the application of NHCs as Lewis base catalysts. We recently developed an all-carbon [4+2] cycloaddition-decarboxylation that typifies this type of catalysis. Herein, the discovery of this methodology, its context and...

The synthesis of 1-acyl-2-alkylcycloalkenes from a variety of cycloalkanones has been achieved via either β-keto enol phosphates or β-bromoenones. Both methods exploit simple and readily scalable transformations allowing the preparation of the desired compounds to be achieved in three, or four steps, respectively. The utility of these strategies ha...

Herein we report the first all-carbon N-heterocyclic carbene-catalyzed (4 + 2) cycloaddition. The reaction proceeds with α,β-unsaturated acid fluorides and silyl dienol ethers and produces 1,3-cyclohexadienes with complete diastereocontrol (dr >20:1) while demonstrating a new type of reaction cascade exploiting α,β-unsaturated acyl azoliums.

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(Chemical Equation Presented) Catalytic generation of α,β- unsaturated acyl imidazolium cations and enolates has been achieved, and their involvement in a Michael addition acylation sequence exploited, to provide a range of dihydropyranones. α,β-Unsaturated enol esters, or α,β-unsaturated acid fluorides in association with TMS enol ethers, serve as...

The synthesis of a range of α-hydroxymethylated enones has been achieved using the Villiéras modification of the Horner–Wadsworth–Emmons (HWE) reaction. Scope, limitations, and mechanistic aspects of this reaction were investigated using a combination of synthetic and computational studies. These investigations support a Schlosser–Corey type reacti...