Pd-catalyzed Intermolecular Dehydrogenative Heck Reactions of Six-membered Heteroarenes

The Pd^II-mediated cross-coupling of (hetero)arenes with alkenes may be an effective method for the formation of a C–C bond from two C–H bonds. This reaction was discovered by Fujiwara and his co-workers in 1967, which led to a number of reports that we first highlighted in 2011 (review with references till June 2010) and for which we retained the name “Dehydrogenative Heck Reaction” (DHR). The DHR of six-membered heteroarenes has been the subject of intensive research over the last ten years. The present review is limited to these dehydrogenative Heck reactions published since 2010, underlining the diversity of the procedures, mechanisms and intermediates that have been proposed along with some personal comments.