Gold(III)‐chlorid‐katalysierte Dominoprozesse mit intermediären Isobenzopyrylium‐Kationen

Abstract

Ein Potpourri bemerkenswerter Reaktionen wird durch die AuCl3‐katalysierte Cyclisierung eines ortho‐Alkinylbenzaldehyds eingeleitet. Mit Olefinen und elektronenreichen Heteroarenen als Nucleophilen oder Dienophilen wird eine breite Palette von polycyclischen Strukturen selektiv zugänglich.

Gold‐Catalyzed Tandem Cyclization/Cycloaddition Reaction of Enynones: Highly Regioselective Synthesis of Oxabicyclic Compounds and Naphthyl Ketones

“…To our delight, treatment of 1 a in the presence of [L 1 AuCl] (5 mol %) in 1,4-dioxane at 80 8C in air afforded the oxabicyclic compound epoxybenzoA C H T U N G T R E N N U N G [4,5] AuCl] (5 mol %) in 1,4-dioxane (2.0 mL) at 80 8C in air for 20 h was found to be an optimal set of conditions to form 2 a (conditions A), and the use of 3 )Au]SbF 6 (5 mol %) in 1,4-dioxane (1.0 mL) at 80 8C in air for 10 h was considered as standard conditions for producing 3 a (conditions B).…”

“…[2] In particular, or [3+2] cycloaddition/ annulation of 2-oxo-1-alkynebenzenes has attracted great attention as an effective approach for the construction of polycyclic compounds. [3,5] Thus, incorporation of this strategy has been highlighted in the synthesis of natural products. [4] However, much effort has been focused on enynals in this area, [3] and little attention has been paid to enynones.…”

“…[3,5] Thus, incorporation of this strategy has been highlighted in the synthesis of natural products. [4] However, much effort has been focused on enynals in this area, [3] and little attention has been paid to enynones. [5, 8d-i] Therefore, the exploration of an efficient reaction with enynones still needs to be actively pursued.…”

Efficient Palladium‐Catalyzed Oxidative Indolation of Allylic Compounds with DDQ via sp3 CH Bond Activation and Carbon‐Carbon Bond Formation Under Mild Conditions

“…[1] The development of new, efficient and selective synthetic methods for the functionalization of indoles continues to receive considerable attention. [2] With the emergence of the concepts of "atom economy" [3] and "green chemistry" [4] transition metal-catalyzed C À H bond activation directly to form C À C bond has attracted great attention recently and a number of excellent results have been obtained. [5] Various oxidative intermolecular cross-dehydrogenative-coupling (CDC) reactions by using two different C À H bonds have also been developed, such as (i) sp 3 C À H with sp 3 C À H, [6] (ii) sp 2 C À H with sp 2 C À H, [7] (iii) sp 3 C À H with sp 2 C À H, [8] and (iv) sp 3 C À H with sp C-H. [9] The palladium-catalyzed allylic alkylation (TsujiTrost coupling reaction), usually employing an allylic acetate or its derivatives, and later using allylic alcohols directly as the starting material, represents one of the most common C À C bond formation methodologies in organic synthesis.…”

Gold-Catalyzed Benzylation of Arenes and Heteroarenes

“…[1] In addition to industrially important oxidation processes, which proceed in the presence of heterogeneous gold catalysts, [2] more and more organic reactions are discovered to be catalyzed by homogeneous gold complexes. So far, mainly hydrogenations, [3] isomerizations, [4] aldol reactions, [5] reactions of alkynes with nucleophiles, [6] reactions of propargyl or allenyl ketones , [7] additions of electron-rich arenes to methyl vinyl ketones, [8] and domino processes with isobenzopyrylium cation intermediates [9] have been discovered. Recently published articles include the synthesis of oxazoles, [10] domino hydroarylation and cycloisomerization reactions, [11] transformations of alkynyl epoxides to furans [12] and the benefits of N and N,O ligands in gold-catalyzed reactions.…”