Oxidative Alkenylation/Annulation of Benzimidates via Ruthenium(II)‐Catalyzed CH Activation to Generate 3‐Methyleneisoindolin‐1‐ones

Abstract

A novel ruthenium-catalyzed oxidative alkenylation/annulation cascade reaction is described for synthesizing 3-methyleneisoindolin-1-ones. In the protocol, the N À H imidate is applied efficiently as a directing group in ruthenium-catalyzed C À H activation, generating various 3-methyleneisoindolin-1-ones with high regio-and stereoselectivity in moderate to good yields.

Synthesis of Isoindolinones by Pd-Catalyzed Coupling between N-Methoxybenzamide and Styrene Derivatives

“…The hydrogenation reaction is known to proceed well in high yields for similar benzylideneisoindolidinones, when the exocyclic alkene contains an electronwithdrawing ester group. 9,14 In the present case, the reduction of aryl-substituted 2required slightly elevated temperatures of between 40-50 °C. This was attributed to the twisted alkene moiety observed in the X-ray crystal structure (See Supporting Information), sterically hindering the accessibility to surfaceadsorbed hydrides.…”

Diastereoselective Trifluoromethylation of Chiral α,β‐Unsaturated N‐tert‐Butanesulfinyl Ketimines with Ruppert‐Prakash Reagent: Asymmetric Synthesis of α‐Tertiary Trifluoromethyl Allylic Amines

“…Their versatility can be attributed to the presence of the strongly electron withdrawing trifluoromethyl group which can tune the basicity of amines and thus enhance the lipophilicity, metabolic stability and bioactivity of a target drug molecule . Therefore, great efforts have been devoted to their asymmetric synthesis . However, most of the reported methods focus on the preparation of chiral α‐secondary trifluoromethyl allylic amines .…”

“…More recently, our group developed a general and efficient method for the asymmetric synthesis of structurally diverse α‐tertiary trifluoromethyl allylic amines by the regioselective addition of organolithium reagents to chiral trifluoromethyl α,β‐unsaturated N ‐ tert ‐butanesulfinyl ketimines (Scheme , eq. a) . However, the use of organolithium reagents is known to make the reaction process considerably tedious and this severely restricts their application in such processes.…”

“…This is primarily due to their ambident electrophilic character which results into a competition between the 1,2‐ and 1,4‐addition reactions . As a continuation of our interest in the chemistry of chiral α,β‐unsaturated N ‐ tert ‐butanesulfinyl ketimines, we report herein the first highly regio‐ and diastereoselective trifluoromethylation of chiral α,β‐unsaturated N ‐ tert ‐butanesulfinyl ketimines with the Ruppert‐Prakash reagent (TMSCF 3 ) (Scheme , eq. b).…”

“…The absolute configuration of the product 3 a was assigned as ( Rs , R ) upon the removal of the N ‐sulfinyl group under acidic conditions, followed by the comparison of the optical rotation with that of a known compound ,. The absolute configurations of the products 3 b – n were assigned by analogy.…”