The first now named Stille reaction was published 38 years ago, and the last comprehensive revision of this catalysis was in 2004. Since then the knowledge of the different steps of the three possible (and sometimes competing) reaction pathways (cyclic, open, and ionic) has been almost completed by synergistic experimental and theoretical studies: the Stille reaction is perhaps the best characterized catalytic process if we consider the number of intermediates that have been detected. This review concentrates on the mechanistic new knowledge, and on important aspects as the revolution with the use of bulky phosphines, the bimetallic alternative of the Stille reaction, the enantioselectivity in Stille and palladium free Stille processes, the meaning of copper effect, or the possible approaches to make Stille coupling a greener process.

Complexes [AuCl{C(NHR)(NHR 0 )}] and [AuCl{C(NHR)(NEt 2 )}] (R= t Bu, p-Tol, Xylyl, p-C 6 H 4 -COOH, p-C 6 H 4 COOEt, R 0 = Me, n Bu, i Pr, n heptyl, p-Tol) have been prepared by reaction of the corresponding isocyanogold complexes [AuCl(CNR)] with either primary amines or diethylamine. All the prepared carbenes are reactive and highly selective catalysts for skeletal rearrangement, methoxycyclization of 1,6-enynes, and other mechanistically related gold-catalyzed transformations. Overall, these easily accessible nitrogen acyclic carbene (NAC) gold complexes were not second to NHC complexes and were advantageous to obtain different products.

A new generation of porous polymer networks has been obtained in quantitative yield by reacting two rigid trifunctional aromatic monomers (1,3,5-triphenylbenzene and triptycene) with two ketones having electron-withdrawing groups (trifluoroacetophenone and isatin) in superacidic media. The resulting amorphous networks are microporous materials, with moderate Brunauer-Emmett-Teller surface areas (from 580 to 790 m g), and have high thermal stability. In particular, isatin yields networks with a very high narrow microporosity contribution, 82% for triptycene and 64% for 1,3,5-triphenylbenzene. The existence of favorable interactions between lactams and CO molecules has been stated. The materials show excellent CO uptakes (up to 207 mg g at 0 °C/1 bar) and can be regenerated by vacuum, without heating. Under postcombustion conditions, their CO/N selectivities are comparable to those of other organic porous networks. Because of the easily scalable synthetic method and their favorable characteristics, these materials are very promising as industrial adsorbents.

Isocyanide [AuX(CNPy-2)] (X = Cl, C6F5, fluoromesityl, 1/2 octafluorobiphenyl) and carbene [AuX{C(NR1R2)(NHPy-2)}] (R1R2NH = primary or secondary amines or 1/2 primary diamine) gold(I) complexes have been synthesized and characterized. For X = Cl, the carbene complexes show aurophilic interactions. The fragment NHPy-2, formed in the carbenes, can give rise to intra- (for primary amines) or intermolecular (for secondary amines) hydrogen bonds, depending on the amine used. These bonds and contacts have been studied in the solid state and in solution. The intermolecular hydrogen bonds are split in an acetone solution, but the intramolecular ones, which close a six-membered ring, survive in solution. Except for the fluoromesityl derivatives, the carbene complexes display luminescent properties.

Complexes [AuCl{C(NHR)(NHPy-2)}] (Py-2 ) 2-pyridyl; R ) Me, tBu, nBu, iPr, nheptyl) have been prepared in amodular way from [AuCl(CNPy-2)]. The carbene moiety has a hydrogen-bond supported heterocyclic structure similar to the nitrogen heterocyclic carbenes in the solid state, and in CH2Cl2 or acetone solution, which is open in the presence of MeOH. The compounds are good catalysts for the skeletal rearrangement of enynes, and for the methoxycyclization of enynes. In contrast, the complexes [AuCl{C(NHR)(NHPy-4)}] are scarcely active due to the blocking effect of the coordination position required for the catalysis by the nitrogen of the NHPy-4 group.

Mononuclear and dinuclear chiral gold(I) carbene complexes with carbene ligands of the type HBHC (hydrogen bonded heterocyclic carbenes) and NAC (nitrogen acyclic carbenes) have been prepared by reaction of isocyanide gold(I) complexes and chiral amines or diamines. The reaction of [AuCl(CNPy-2)] (1) (Py = pyridyl) with the corresponding chiral primary amines afforded the chiral HBHC complexes (R)-[AuCl{C(NH(CHMePh))(NHPy-2)}] ((R)-2), and (S)-[AuCl{C(NH{CHMe(1-naphthyl)})(NHPy-2)}] ((S)-3), while the reaction of 2 equiv of 1 with diamines produced (S)-2,2'-bis[NH{C(AuCl)(NHPy-2)}](2)-binaphthyl ((S)-4), (1R,2R)-1,2-bis[NH{C(AuCl)(NHPy-2)}]-diphenylethane ((1R,2R)-5), and (1R,2R)-1,2-bis[NH{C(AuCl)(NHPy-2)}]-cyclohexane ((1R,2R)-6). On the other hand the addition of alkyl amines to (S)-2,2'-[NCAuCl](2)-binaphthyl ((S)-8) gave the chiral NAC complexes (S)-2,2'-bis[NH{C(AuCl)(NMe(2))}](2)-binaphthyl ((S)-9) and (S)-2,2'-bis[NH{C(AuCl)(N(i)Pr(2))}](2)-binaphthyl ((S)-10), while the addition to (S)-2,2'-[NCAuCl](2)-3,3'-Ph(2)-binaphthyl ((S)-12) yielded (S)-2,2'-bis[NH{C(AuCl)(NMe(2))}](2)-3,3'-Ph(2)-binaphthyl ((S)-13) and (S)-2,2'-bis[NH{C(AuCl)(NEt(2))}](2)-3,3'-Ph(2)-binaphthyl ((S)-14). All the complexes are active catalysts in the cyclopropanation of vinyl arenes and in the intramolecular hydroalkoxylation of allenes, providing good yields and modest or poor enantioselectivity. The results show that all these ligands are compatible with different functions and reaction conditions and are worth considering as alternative systems to NHCs or phosphines in gold catalyzed reactions.

Complexes containing one or two Fmes ligands (Fmes = 2,4,6-tris(trifluoromethyl)phenyl = nonafluoromesityl) either trans or cis are obtained by treating palladium(II) chloro complexes with Li(Fmes):  trans-[PdCl2L2] (L = tetrahydrothiophene (tht), PPh3) lead to trans-[Pd(Fmes)ClL2] (L = tht, PPh3) or trans-[Pd(Fmes)2L2] (L = tht); [PdCl2(L-L)] (L-L = 1,5-cyclooctadiene, 2,2‘-bipyridine) give [Pd(Fmes)Cl(L-L)] (L-L = COD, bipy) or [Pd(Fmes)2(bipy)]. The structures of two complexes containing two Fmes ligands in trans and cis arrangement, trans-[Pd(Fmes)2(tht)2] (2) and [Pd(Fmes)2(bipy)] (6), respectively, have been determined by X-ray diffraction. In spite of the severe steric congestion the complexes are four coordinated. Distortions due to the bulkiness of the ortho substituents and short Pd···F3C-ortho distances are observed. The high degree of steric crowding is also responsible for slow rotation around the Pd−P bonds in the complex trans-[Pd(Fmes)Cl(PPh3)2]. ΔG ⧧ associated with this motion is 12.8 kcal mol-1, one of the highest values reported so far for rotation around M−PPh3 bonds. Complexes 2 and 6 are redox inactive by cyclic voltammetry in the range −1.8 to +1.8 V.

A subtle interplay of coValent bond, hydrogen bond, aurophilic interactions, and steric hindrance controls the nuclearity and the luminescent properties of [Au{2-PyNd C(E)Me}] n (E ) O, NH) complexes. For E ) O a molecular structure with n ) 4 is formed, describing a 20-membered tetrametallacycle. For E ) NH the structure formed shows a trigonal prismatic arrangement of six gold atoms formed by gold-gold interactions between two gold triangles (n ) 3 × 2). Both complexes display luminescent properties.