Illuminating -hydrozirconation: controlled geometric isomerization of an organometallic species.

A general strategy to enable the formal -hydrozirconation of arylacetylenes is reported that merges -hydrometallation using the Schwartz Reagent (CpZrHCl) with a subsequent light-mediated geometric isomerization at = 400 nm. Mechanistic delineation of the -thermodynamic isomerization step indicates that a minor reaction product functions as an efficient generated photocatalyst. Coupling of the -vinyl zirconium species with an alkyne unit generates a conjugated diene: this has been leveraged as a selective energy transfer catalyst to enable → isomerization of an organometallic species.

Light-Enabled Enantiodivergence: Stereospecific Reduction of Activated Alkenes Using a Single Organocatalyst Enantiomer.

Light-enabled enantiodivergence is demonstrated in which the alkene substrate configuration is manipulated ( → ) prior to organocatalytic reduction with a chiral thiourea and Hantzsch ester. This allows stereodivergent reduction to be regulated at the substrate level with high fidelity and mitigates the need for a second, enantiomeric catalyst (up to 93:07 and 95:5 ). The synthetic utility of this strategy has been demonstrated in the synthesis of the weight-loss drug ()-Lorcaserin (Belviq) and a potent AMPA modulator.