An asymmetric rhodium­(III)-catalyzed Grignard-type addition of inert arene C–H bond to aldehydes is reported. It provides a new strategy for the synthesis of chiral 3-substituted phthalides in good yields (up to 87%) with high enantiomeric purity (up to 99% ee). Interestingly, a chiral-matching effect between substrate and catalyst was observed, which is crucial to accomplish satisfied reaction outcomes. Mechanistically, the reaction is assumed to proceed via consecutive C­(sp 2)–H activation of benzamide, addition to aldehyde, and lactonization.

A straightforward and convenient route has been developed for the synthesis of 3‐unsubstituted phthalide derivatives from aryl amides and paraformaldehyde by ruthenium(II)‐catalyzed C–H activation. The reaction proceeds through tandem ortho‐hydroxymethylation of aryl amide and subsequent intramolecular lactonization.

By using a chiral directing group, an asymmetric rhodium(III)-catalyzed CÀ H bond addition to aldimines followed by intramolecular cyclization to form chiral isoindolinones has been achieved (up to 68 % yield, up to 93 % ee). A three-component variant that resembles Mannich reaction was also realized (41 % yield, 83 % ee). Product elaborations and preliminary mechanistic studies were described.

No abstract

No abstract