Silyl-Group Boosted Internal Redox Reaction: Hydride Shift from an Aliphatic Secondary Position for the Formation of Six- and Seven-Membered Carbocycles

Abstract

We report a hydride shift/cyclization reaction at the aliphatic secondary position (methylene group). The key to accomplishing this reaction was the employment of benzylidene malonate having a silyl group β to the hydride donor carbon. When the corresponding malonates were treated with a catalytic amount of Al(OTf) 3 , the [1,5]-hydride shift from the simple aliphatic secondary position proceeded smoothly to afford silyl-group substituted tetralin derivatives in excellent chemical yields (up to 98%). This reaction system was applied to the formation of sevenmembered carbocycles via the [1,6]-hydride shift mediated process.

Synthesis of Polysubstituted Naphthalenes by a Hydride Shift Mediated C–H Bond Functionalization/Aromatization Sequence

“…Based on this strategy, transformations including the double C­(sp 3 )–H bond functionalization and the sequential system involving the C­(sp 3 )–H bond functionalization/Friedel–Crafts reaction have been developed. Herein we report a new entry in related chemistry: C­(sp 3 )–H bond functionalization/aromatization sequence for the synthesis of polyaromatic compounds …”