Ruthenium(II)-Catalyzed Redox-Free [3 + 2] Cycloaddition of N-Sulfonyl Aromatic Aldimines with Maleimides

Abstract

A ruthenium(II)-catalyzed redox-free cycloaddition of N-sulfonyl aromatic aldimines with maleimides providing 1-aminoindanes in good yields is described. Usually, maleimides reacted with substituted aromatics, affording the Michael-type ortho alkylated aromatics or 1,1-type cyclized spirosuccinimides. In the present reaction, maleimides provided 1,2-type cycloaddition products. The proposed mechanism was strongly supported by the DFT calculations and isolation of a ruthenacycle intermediate.

Maleimides in Directing‐Group‐Controlled Transition‐Metal‐Catalyzed Selective C−H Alkylation

“…In 2018, Jeganmohan reported an efficient synthesis of 1‐aminoindanes through the Ru(II)‐catalyzed cycloaddition of N ‐sulfonyl aromatic aldimines with maleimides (Scheme 38). [41] Dimethyl maleate was also suitable alkylation reagent. In the catalytic reaction, 1,2‐type cycloaddition products were obtained rather than the Michael‐type ortho alkylated aromatics or 1,1‐type cyclized spirosuccinimides.…”

“…In 2018, Jeganmohan reported an efficient synthesis of 1aminoindanes through the Ru(II)-catalyzed cycloaddition of Nsulfonyl aromatic aldimines with maleimides (Scheme 38). [41] Scheme 33. Ru(II)-catalyzed site-selective addition of ortho CÀ H bond of acetophenones or C-2 position of indoles to maleimides.…”

The Role of Sulphonamides and N‐Sulphonyl Ketimines/Aldimines as Directing Groups in the Field of C−H Activation

“…Kim and co‐workers [66] & Jeganmohan [67] and co‐workers employed N ‐sulphonyl aldimines ( 106 ) as substrate with maleimides ( 107 ) as coupling partner to achieve diastereoselective synthesis of ubiquitous scaffold like 1‐aminoindane derivatives ( 108 ) using different reaction conditions as mentioned in Scheme 30. Indanes are biologically significant as having properties like anti‐inflammatory, analgesic, anti‐convulsant etc.…”

Transition metal-catalyzed coupling of heterocyclic alkenesviaC–H functionalization: recent trends and applications

“…In addition, the Jeganmohan group showed the Ru-catalyzed cycloaddition of N-sulfonyl aryl aldimines with maleimides (Scheme 88B). 137 The N-sulfonyl directing group and acetate ion sources are crucial for the success of this reaction. This strategy is extended to the construction of succinimide linked oxindoles.…”