RhIII-Catalyzed Regioselective Preparation of 3-Hetero-Substituted Isocoumarins from Aryl Carboxylic Acids and Alkynes

Synthesis of C3-sulfone substituted naphthols via rhodium(III)-catalyzed annulation of sulfoxonium ylides with alkynylsulfones

C-H activation of sulfoxonium ylides catalyzed by rhodium(iii) with subsequent annulation by alkynylsulfones was accomplished. This methodology offers a step-economical approach for assembling C3-sulfone-substituted naphthols with a high level of regioselectivity that is complementary to previous protocols. The approach has an extensive substrate spectrum and broad functional group tolerance.

A Rh(iii)-catalyzed C–H activation/regiospecific annulation cascade of benzoic acids with propargyl acetates to unusual 3-alkylidene-isochromanones

We developed a new approach to synthesize isochromanones with benzoic acids and propargyl acetates, which introducing an unusual exocyclic C–C double bond at the 3-position with high regioselectivity and moderate to excellent yields.

Concise Synthesis of Isocoumarins through Rh-Catalyzed Direct Vinylene Annulation: Scope and Mechanistic Insight

Transition-metal-catalyzed activation of inert C-H bonds and subsequent C-C bond formation have emerged as powerful synthetic tools for the synthesis of elaborate cyclic molecules. In this report, we introduce an efficient synthetic method of 3,4-unsubstituted isocoumarins adopting an electron-deficient Cp^ERh complex as the catalyst. The use of vinylene carbonate as a vinylene transfer reagent enables the direct construction of isocoumarins from readily available benzoic acids, without any external oxidants as well as bases. The reaction mechanism is evaluated by computational analysis to find an unprecedented "rhodium shift" event within the catalytic cycle.

Regioselective Synthesis of α-Phosphinoylnaphthols through Rhodium-Catalyzed Annulation of 1-Alkynylphosphine Oxides with Sulfoxonium Ylides

α-Phosphinoylnaphthols were obtained by redox-neutral annulation­ of 1-alkynylphosphine oxides with α-carbonyl sulfoxonium ylides under rhodium(III) catalysis. This protocol shows good regio­selectivity and broad functional-group tolerance.

Rhodium(III)-Catalyzed C-H Activation: A Cascade Approach for the Regioselective Synthesis of Fused Heterocyclic Lactone Scaffolds

A Rh(III)-catalyzed cascade C-H activation; regioselective [4 + 2] oxidative annulation; and lactonization of aromatic acids, anhydrides, and acrylic acid derivatives with 4-hydroxy-2-alkynoates have been disclosed. This strategy leads to fused heterocyclic lactone scaffolds in a single step with moderate functional group tolerance and excellent site selectivity. Besides, in one step, an antipode of the cephalosol intermediate natural product that contains a tricyclic isocoumarin framework has been synthesized.

Ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of benzylic alcohols with internal alkynes: entry to isocoumarins

A new ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of primary benzylic alcohols with internal alkynes is described, which enables benzylic alcohols as weakly directing group precursors to access isocoumarins via multiple C-H functionalization. The reaction works well with a broad substrate scope, tolerates a wide range of functional groups, and incorporates practically the isocoumarin unit into diverse bioactive molecules. Mechanistic studies indicate that activation of aryl C(sp²)-H bonds is achieved through the generation of the active benzoyloxy-Ru(ii) intermediates via oxidation of benzylic alcohols using an electrooxidative Ru(ii) catalyst.

Controllable construction of isoquinolinedione and isocoumarin scaffolds via RhIII-catalyzed C–H annulation of N-tosylbenzamides with diazo compounds

An efficient protocol for the synthesis of isoquinolinediones by Rh^III-catalyzed C–H activation/annulation/decarboxylation of N-tosylbenzamides with diazo compounds is reported.

Rapid synthesis of 3-amino isocoumarin derivatives from ynamides

A novel and efficient fast synthesis of 3-amino isocoumarins in good to excellent yields is reported.

Copper-catalyzed one-pot reactions of acetyl chloride, o-halobenzoic acids and Wittig reagents toward 3-methyl isocoumarin synthesis

The synthesis of 3-methtyl isocoumarins is achieved via the copper-catalyzed one-pot reactions of Wittig reagents, acetyl chloride and o-iodobenzoic acids via tandem construction of CC, C–O and C–C bonds.