<i>B</i>-Alkylcatecholborane-Mediated Tandem Radical Conjugated Addition−Aldol Cyclization

A one-pot procedure involving radical conjugate addition of <i>B</i>-alkylcatecholboranes to enones followed by intramolecular aldol reaction is reported. Application to the stereoselective synthesis of monocyclic and bicyclic products with up to four contiguous stereogenic centers is presented.