Cascade Cyclizations of α,ß-Unsaturated Thioesters: Additional Examples.

Several additional examples of cascade cyclizations of α,ß-unsaturated thioesters proceeding are reported, which proceed via two distinct mechanistic pathways: enantioselective acyl transfer promoted by amidine-based catalysts (ABCs) and a racemic chain mechanism mediated by a thiolate nucleophile.

Organocatalyzed Rearrangement of S-(2-Oxoalkyl)-thioenoates.

The highly Lewis basic amidine-based catalyst DHIP promotes the rearrangement of S-phenacyl thiocinnamate and related thioesters into dihydrothiophene derivatives. In contrast to previously explored rearrangements of thioesters, the reaction proceeds via a novel Dieckmann-like cyclization pathway. An alternative two-component synthesis of the same products has also been developed.