Modular C–H Functionalization Cascade of Aryl Iodides

We report the first example of <i>ipso</i>-borylation for the modular 1,2-bisfunctionalization of aryl iodides via C–H functionalization. The carbon–boron bond is used as a lynchpin to access <i>ipso</i> carbon–carbon, carbon–nitrogen, carbon–oxygen, and carbon–halogen (Cl, Br, I) bonds. The utility of our methodology is illustrated through quick, modular syntheses of the pharmaceuticals Abilify and Flunixin

Palladium-Catalyzed Cross-Coupling Reactions with Zinc, Boron, and Indium Exhibiting High Turnover Numbers (TONs): Use of Bidentate Phosphines and Other Critical Factors in Achieving High TONs^†

Palladium-catalyzed reactions of unsaturated organozincs with aryl or alkenyl iodides can exhibit turnover numbers (TONs) over 105 (>70% product yields). Under the conditions employed, Zn, B, and In appear to be the three most favorable metals, followed by Al(Zn) and Zr(Zn), whereas TONs observable with Sn, Cu, and Mn have been significantly lower

Palladium-Catalyzed Cross-Coupling Reactions with Zinc, Boron, and Indium Exhibiting High Turnover Numbers (TONs): Use of Bidentate Phosphines and Other Critical Factors in Achieving High TONs^†

Palladium-catalyzed reactions of unsaturated organozincs with aryl or alkenyl iodides can exhibit turnover numbers (TONs) over 105 (>70% product yields). Under the conditions employed, Zn, B, and In appear to be the three most favorable metals, followed by Al(Zn) and Zr(Zn), whereas TONs observable with Sn, Cu, and Mn have been significantly lower

Synthesis of Substituted Pyrazoles via Tandem Cross-Coupling/Electrocyclization of Enol Triflates and Diazoacetates

The synthesis of 3,4,5-trisubstituted pyrazoles via a tandem catalytic cross-coupling/electrocyclization of enol triflates and diazoacetates is presented. The initial scope of this methodology is demonstrated on a range of differentially substituted acyclic and cyclic enol triflates as well as an elaborated set of diazoacetates to provide the corresponding pyrazoles with a high degree of structural complexity

Evelynin, a Cytotoxic Benzoquinone-Type <i>retro</i>-Dihydrochalcone from <i>Tacca chantrieri</i>

A new benzoquinone-type retro-dihydrochalcone, named evelynin, was isolated from the roots and rhizomes of Tacca chantrieri. The structure was elucidated on the basis of the analysis of spectroscopic data and confirmed by a simple one-step total synthesis. Evelynin exhibited cytotoxicity against four human cancer cell lines, MDA-MB-435 melanoma, MDA-MB-231 breast, PC-3 prostate, and HeLa cervical carcinoma cells, with IC50 values of 4.1, 3.9, 4.7, and 6.3 μM, respectively