Practical access to diversely functionalized carbazoles has been developed by consecutive Cu-catalyzed Chan-Lam NÀ arylation of various o-iodoanilines and boronic acids, and Pd-catalyzed intramolecular aryl CÀ H activation of 2-iodo-N-arylanilines. Use of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base was found beneficial for both steps. In the Pd-catalyzed CÀ H activation step, DBU acts as ligand as well as base, resulting in improved functional tolerance and higher yields than those observed with inorganic or other nitrogen bases. This DBU-assisted sequence offers access to a variety of carbazoles with various electron-donating and electron-withdrawing substituents, including halogens or other reactive functional groups. Twentyseven cabazoles with various substitution paterns, including two naturally-occurring carbazoles -clausine L and clausine Hhave been successfully synthesized using these DBU-promoted metal-catalyzed coupling reactions.

Organoboron compounds, especially alkenylboronates and arylboronates are highly useful reagents and versatile building blocks in the modern synthetic chemistry toolbox. This review focuses on copper-catalyzed routes to access alkenyl-and arylboronate esters. Various copper salts and ligands have been employed to access them in excellent regio-and stereoselectivity as well as high yields. Both addition and substitution reactions to alkenylboronates have been highlighted based on various methodologies including hydroboration, carboboration, borylative opening of propargyl three-and four-membered rings, dehalogenative borylation of alkenyl bromides and iodides, defluoroborylation of fluoroalkenes and direct C(sp 2 )À H bond activation of alkenes. Preparation of arylboronates involving borylation of aryl halides, C(sp 2 )À H borylation of arenes and cascade 1,3-halogen migration/borylation of 2halostyrenes have been reviewed. Mechanistic aspects of those borylation reactions are discussed briefly.

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