Palladium-catalyzed oxidative arylhalogenation of alkenes: synthetic scope and mechanistic insights.
This article describes the development of a Pd-catalyzed reaction for the arylhalogenation (halogen = Cl or Br) of diverse alpha-olefins by oxidatively intercepting Mizoroki-Heck intermediates. These transformations afford synthetically useful 1,2- and 1,1-arylhalogenated products in good yields with good to excellent selectivities that can be modulated by changing the nature of the halogenating reagent and/or the reaction conditions. The selectivity of these reactions can be rationally tuned by (i) controlling the relative rates of oxidative functionalization versus beta-hydride elimination from equilibrating Pd(II)-alkyl species and (ii) stabilization of organometallic Pd(II) intermediates through the formation of pi-benzyl adducts. These arylhalogenations exhibit modest to excellent levels of stereoselectivity, and the key carbon-halogen bond-forming step proceeds with predominant retention of stereochemistry at carbon.
University of Michigan, Department of Chemistry, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.
Dipannita
D
Kalyani
Andrew D
AD
Satterfield
Melanie S
MS
Sanford
D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D054879:Halogenation; D009281:Naphthalenes / Q000737:chemistry; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism; D020058:Styrene / Q000737:chemistry; D013379:Substrate Specificity
D000475:Alkenes; D009281:Naphthalenes; D012997:Solvents; C031721:naphthalene; D020058:Styrene; D010165:Palladium