When these compounds are ligated to metal atoms, they can be classified as Fischer electrophilic piÂ­acceptors or Schrock nucleophilic piÂ­donors.
Phenols can be orthoÂ­formylated by reacting them with these compounds in the ReimerÂ–Tiemann ("RYEÂ­mer TEEÂ­mon") reaction. When the catalyst rhodium(II) acetate is reacted to generate in situ compounds with this functionality, they can simultaneously effect CÂ–H activation and Cope rearrangement reactions. These compounds are most often formed from either alphaÂ­elimination reactions or the photolysis of diazoÂ­compounds. The ligand IMes ("eyeÂ­MESS"), first formulated by (*) Arduengo, is an "NÂ­heterocyclic" compound containing this functionality that is present in the second generation Grubbs catalyst. They most often react by inserting themselves into CÂ–H, HÂ–heteroatom, and CÂ–C bonds, or by the cyclopropanation of alkenes. When these compounds are ligated to metal atoms, they can be classified as Fischer electrophilic piÂ­acceptors or Schrock nucleophilic piÂ­donors. For 10 points, name these compounds containing a neutral, divalent carbon atom that has a lone pair.
Phenols can be orthoÂ­formylated by reacting them with these compounds in the ReimerÂ–Tiemann ("RYEÂ­mer TEEÂ­mon") reaction.
carbene