A Stepwise Synthesis of Spiroindoline Compounds via Ring Opening of Aziridines and C−H Activation/Cyclization

Abstract

A type of 2,2‐disubstituted N‐sulfonylaziridines bearing OTBS groups and aryl groups at two different substitutions of the aziridine ring has been prepared. Based on them, a stepwise strategy involving ring opening of aziridines and C−H activation/cyclization has been developed for the general synthesis of spiroindoline pyrans and spiroindoline furans.

Three-Component Couplings among Heteroarenes, Difluorocyclopropenes, and Water via C–H Activation

“…Transition-metal-catalyzed direct functionalization of inert C–H bonds has attracted considerable attention as it provided practitioners in the synthetic community with a powerful and convenient protocol for rapidly constructing numerous valuable molecules in an atom- and step-economic manner. − Over the past few decades, organic chemists have spent a great deal of effort in pursuing directing group (DG)-assisted C–H bond functionalization, through which a large array of desired molecules with structural diversity and complexity could be obtained by using efficient coupling partners. − Among them, strained rings such as aziridines, − cyclopropanols, − and alkylidenecyclopropanes − have stood out as charming coupling partners because they enabled rapid reconstruction of the skeleton of the product and then achieved structural complexity with the inherent ring strain being the driving force. Being one of the most appealing strained molecules, cyclopropenone has been widely applied as a building block for quick access to various heterocyclic compounds under Rh or Ru catalysis via the C–H activation strategy. − Despite the great progress that has been made, some drawbacks in the preparation of cyclopropenone such as the tedious procedure and high cost limited its further application (Scheme a).…”