Asymmetric cyclocondensation of N-sulfonylimines with fluoroacetic acid promoted by isothiourea catalyst HBTM-2 generates 3-fluoro-β-lactams with high enantio-and diastereoselectivity. These reactive compounds are opened with alcohols or amines to produce the corresponding αfluoro-β-amino acid derivatives in moderate yields.

No abstract

Racemic cyclic hydroxamic acids bearing an aryl substituent adjacent to the hydroxyl group undergo effective acylative kinetic resolution promoted by benzotetramisole (BTM).

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.

Several additional examples of cascade cyclizations of α,β-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. Note pubs.acs.org/joc