Cobalt-catalyzed multi-substituted alkene synthesis from 1,3-dithiolanes and Grignard reagents

The cobalt-catalyzed reaction between 1,3-dithiolanes and Grignard reagents, for the efficient synthesis of multi-substituted alkene products, is described. The method was applicable to a variety of benzylic dithiolane substrates, affording di-, tri-, and tetra-substituted 1,1-diaryl alkene products in good to excellent yields. The use of benzylic Grignard reagents with aryl aldehyde-derived 1,3-dithiolanes enabled access to natural product-derived stilbene architectures with exquisite E selectivity. The operational simplicity, low catalyst loadings, and scalability demonstrate the general utility of the method