From insects to cancer: N-Cyano sulfoximines were evaluated for COX inhibition and antiproliferative activity against a panel of cancer cell lines. The most active compound exhibited potent COX-2 inhibition, some selectivity for COX-2 over COX-1, only slight cytotoxicity towards healthy cells (HaCaT skin cells), and no mutagenic potential (as determined by an Ames assay).

Two enantioselective total syntheses of the nortriterpenoid natural product rubriflordilactone A are described, which use palladium- or cobalt-catalyzed cyclizations to form the CDE rings, and converge on a late-stage synthetic intermediate. These key processes are set up through the convergent coupling of a common diyne component with appropriate AB-ring aldehydes, a strategy that sets the stage for the synthetic exploration of other members of this family of natural products.

Benzimidazoles are prepared by intramolecular N-arylations of amidines mediated by potassium hydroxide in DMSO at 120 °C. In this manner, diversely substituted products have been obtained in moderate to very good yields.

Carbamoyl fluorides are formed in reactions of hydroxylamines with difluorocarbene generated from sodium bromodifluoroacetate as readily available andn on-toxic carbene precursor. The process showsahigh functional group tolerance, and the reactionp ath hasb een rationalized by computational calculations.[a] Reaction conditions:N ,N-dibenzylhydroxylamine (1a, 0.25 mmol) and BrCF 2 CO 2 Na (D,0.50 mmol) in DMF. [b] Addition of K 2 CO 3 (2 equiv.).Scheme 3. Formation of 9 from sodium bromodifluoroacetate (D)a nd N,N-dibenzylhydroxylamine( 1a)( relative free energies to D and 1a in kcal mol À1 ).

The development of complementary palladium- and cobalt-catalyzed approaches to tricyclic arylsilanes suitable for elaboration into the CDE ring systems of rubriflordilactones A and B is reported. Microwave conditions are required to effect a cobalt-catalyzed triyne cyclotrimerization, which critically depends on the substitution pattern of the triyne termini. Mild conditions to elaborate these arylsilanes to the CDE cores of the natural products are described.