ABSTRACT
Nickel was identified as a catalyst for the cyclopropanation of unactivated olefins by using inâ situ generated lithiomethyl trimethylammonium triflate as a methylene donor. A mechanistic hypothesis is proposed in which the generation of a reactive nickel carbene explains several interesting observations. Additionally, our findings shed light on a report by Franzen and Wittig published in 1960 that had been retracted later owing to irreproducibility, and provide a rational basis for the systematic development of the reaction for preparative purposes as an alternative to diazomethane or Simmons-Smith conditions.
ABSTRACT
A mild and practical protocol for the copper-mediated trifluoromethylation of aryl and heteroaryl boronic acids using NaSO(2)CF(3) (Langlois' reagent) and TBHP is described. The reaction proceeds at room temperature under ambient conditions, and the products can be readily purified by extraction or column chromatography.
Subject(s)
Boronic Acids/chemistry , Copper/chemistry , Indicators and Reagents/chemistry , tert-Butylhydroperoxide/chemistry , Free Radicals/chemistry , Methylation , Molecular StructureABSTRACT
Direct access to trifluoromethyl-substituted aziridines through the use of a protocol in which trifluoromethyl diazomethane is generated in situ and subsequently undergoes addition to activated imines is reported.
