The direct and site-selective transition metal-catalysed N1-, C2- or C3-arylations of indoles have been the subject of almost continuous improve- ments since their discovery in early 1980s. This re- search area is mainly motivated by the biological relevance of this class of compounds in order to pro- pose catalytic alternative syntheses to the well known methodologies involving the formation of the indole ring like the Fischer, Larock, Cacchi, Lautens etc. reactions. Since the late 1990s it has experienced new impulses related to the intensive development of catalytic CH activation. Today, through the in- tensive studies of Buchwald and Hartwig, the N1-ar- ylation of indoles has reached sufficient maturity for both academic and industrial applications. On the other hand, the selective C2- or C3-arylation of in- doles, initiated by Ohta in the middle 1980s, has become a hot research area these last years following the reports of Sames. Surprisingly, only few reports concern the use of heterogeneous catalysts; however, the application of these emerging methodologies seems to be related to the discovery of industrially attractive systems.

Transition Metal‐Catalysed, Direct and Site‐Selective N1‐, C2‐ or C3‐Arylation of the Indole Nucleus: 20 Years of Improvements

Direct and rapid heating by microwave irradiation in combination with sealed vessel processing in many cases enables reactions to be carried out in a fraction of the time generally required using conventional conditions. This makes microwave chemistry an ideal tool for rapid reaction scouting and optimization of conditions, allowing very rapid progress through hypotheses–experiment–results iterations. The speed at which multiple variations of reaction conditions can be performed allows a morning discussion of “What should we try?” to become an after-lunch discussion of “What were the results” Not surprisingly, therefore, many scientists both in academia and industry have turned to microwave synthesis as a front-line methodology for their projects. In this review, more than 220 published examples of microwave-assisted synthetic organic transformations from the 2004 to 2008 literature are discussed. An additional ca. 500 reaction schemes are presented in the Electronic Supplementary Material, providing the reader with an overall number of ca. 930 references in this fast-moving and exciting field.

Controlled microwave heating in modern organic synthesis: highlights from the 2004–2008 literature

Transmetalation of Unsaturated Carbon Nucleophiles from Boron-Containing Species to the Mid to Late d-Block Metals of Relevance to Catalytic C−X Coupling Reactions (X = C, F, N, O, Pb, S, Se, Te)

Xuejun Liu

Papers

Microwave-assisted efficient copper-promoted N-arylation of amines with arylboronic acids.

Microwave-Assisted Efficient Copper-Promoted N-Arylation of Amines with Arylboronic Acids.