Abstract B-Alkylcatecholboranes, easily prepared in situ by hydroboration of alkenes, are powerful radical precursors that can be used for carbon-carbon bond formation. Typical procedures for (a) conjugate addition to enones,(b) conjugate addition to activated alkenes such as vinyl sulfones, and (c) direct allylation are described. Experimentally, these three one-pot reactions are easy to perform. No slow addition of a reagent, a procedure ...