Evolution and Synthetic Applications of the Heck-Matsuda Reaction: The Return of Arenediazonium Salts to Prominence

This review highlights the potential and the versatility of arenediazonium salts as viable alternatives to conventional aryl halides and oxygen-based electrophiles for Pd-catalyzed Heck reactions. It also presents an overview of the field over the last decade, including some historical perspective of the Heck-Matsuda (HM) reaction with general considerations regarding reaction conditions, type of catalysts used, and the application of arenediazonium salts as reagents for the HM arylation of several types of alkenes. Throughout this review, the principal aspects related to reactivity and selectivity are discussed, and when applicable a comparison is made between the HM and the conventional Heck reactions. One-pot procedures that involve generation of the arenediazonium salt in situ from the corresponding aniline have been presented as well as some useful heterogeneous catalytic protocols. Allylic alcohols, conjugated alkenes, unsaturated heterocycles, and unactivated alkenes are capable of being arylated with arenediazonium salts by using simple catalysts such as Pd(OAc)(2) or Pd-2(dba)(3) at room temperature in air and in benign and conventional solvents. In addition to the intramolecular variant of the HM reaction, intermolecular tandem coupling-cyclization processes have also been developed for the construction of a range of oxygen and nitrogen heterocycles. Finally, several applications towards the total synthesis of biologically active natural and nonnatural compounds are highlighted as well as the use of the HM reaction in the synthesis of new chiral, nonracemic ligands.