Asymmetric Lithiation of 2-Alkynyl Aryl Sulfides

Significance

The Toru and Hoppe groups have collaborated to publish this interesting paper on asymmetric lithiation of 2-pyridinyl propargyl sulfides and their subsequent addition to aldehydes or protonation. These reactions proceed with good to moderate stereoselectivity. The alkynyl starting material is basically limited to the substrate indicated. The allenyl products were also shown to proceed in a Ni-catalyzed cross-coupling reaction. The stereochemical inversion associated with the lithium-to-titanium transmetallation is quite interesting.