PdI₂-Catalyzed Synthesis of Heterocycles

Abstract

Some PdI 2 -based complexes have proved to be efficient catalysts for the selective, atom-economical synthesis of different important heterocyclic derivatives starting from very simple building blocks, such as simple or functionalized alkynes, amino alcohols, diamines, carbon monoxide, carbon dioxide, alcohols, water, and oxygen. The synthetic protocols leading to heterocycles have been grouped into three classes of reactions: (a) cycloisomerization of (Z)-2-en-4-yn-1-ols, (Z)-2-en-4-yne-1-thiols, (Z)-(2-en-4ynyl)amines, 2-alkynylbenzyl alcohols to give substituted furans, thiophenes, pyrroles, and 1,3-dihydroisobenzofurans or 1H-isochromenes, respectively; (b) oxidative carbonylation of simple alkynes, 1,5-diynes, functionalized alkynes bearing a suitably placed nucleophilic group, amino alcohols, and diamines to afford substituted maleic anhydrides, functionalized b-and g-lactones, band g-lactams, dihydroindol-2-ones, furans, pyrroles, thiophenes, tetrahydrofurans, oxazolidin-2-ones, oxazolines, cyclic ureas, 4H-3,1-benzoxazines, quinazolin-2-ones, quinolin-4-ones; (c) reductive carbonylation of alkynes to give substituted g-lactones and formation of lactone or anhydride derivatives by additive carbonylation, resulting from the combination between oxidative carbonylation of the triple bond and reduction of a suitable functional group present in the substrate itself. Synthesis of Heterocycles by PdI 2 -Catalyzed Additive and Reductive Carbonylation Reactions 5.Conclusions

Water‐Soluble Group 8 and 9 Transition Metal Complexes Containing a Trihydrazinophosphaadamantane Ligand: Catalytic Applications in Isomerization of Allylic Alcohols and Cycloisomerization of (Z)‐Enynols in Aqueous Medium

“…[28] Palladium, [29] gold [30] and especially ruthenium [31] catalysts have been successfully used to promote such a transformation. However, only one example has been performed in aqueous medium, the study being limited to the commercially available enynol (Z)-3-methylpent-2-en-4-yn-1-ol (R = H).…”

Oxidative Carbonylierungen: Organometallverbindungen (RM) oder Kohlenwasserstoffe (RH) als Nucleophile

“…[29][30][31][32][33][34][35][36][37] Eine andere wichtige Variante der oxidativen Carbonylierung ist die oxidative Carbonylierung von Alkenen und Alkinen, die zur direkten Synthese von acyclischen und heterocyclischen Carbonylverbindungen führt. [12,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] [58] Mit dieser Reaktion konnten symmetrische Ketone in mittleren bis hohen Ausbeuten gewonnen werden, wäh-rend die Zugabe stçchiometrischer Mengen einer Metallverbindung nicht nçtig war.…”

Pentynol to furan conversion – Search for the best trans-[MX2(YNC10H14O)2] catalyst

“…In fact, the poorest catalyst (Y = Ph) is that with less basic Y group. In addition, the Y group also stabilizes the alcohol group of 4-pentyn-1-ol inhibiting ready cyclization to a vinylidene type species observed in the cycloisomerization of 4-pentyn-1-ol promoted by Mo or W carbonyl catalysts [4,[11][12][13][14][15]. No such vinylidene type species was detected in processes catalysed by camphorimine catalysts.…”

“…The search for high efficient and selective catalysts for the synthesis of aromatic or heterocyclic organic compounds, including biologically active species or materials [3][4][5][6][7][8][9][10] in particular through processes that contribute to atom economy and/or less residues are actual targets for synthetic chemistry.…”