Zinc‐Mediated Formation of Trifluoromethyl Ethers from Alcohols and Hypervalent Iodine Trifluoromethylation Reagents

Abstract

Schieb mal rüber: Der Transfer einer intakten Trifluormethylgruppe von einem hypervalenten Iodreagens zu einem aliphatischen Alkohol verläuft glatt bei einer Aktivierung durch Zinkbis(triflimid). Dies ist eine einfache Methode zur Synthese von Trifluormethoxyalkyl‐Derivaten, die sonst nur schwer zugänglich sind.

Catalytic Intramolecular Aminofluorination, Oxyfluorination, and Carbofluorination with a Stable and Versatile Hypervalent Fluoroiodine Reagent

“…Therefore,wesuggest that the metal catalyst, such as Zn(BF 4 ) 2 ,activates 1 to form 8.A similar type of activation of the CF 3 analogue using Zn salts was reported by Togni and co-workers. [17] In the activated complex 8 the hypervalent iodine has al ow-lying empty orbital (formed by cleavage of the iodine-oxygen bond), which is easily accessible for the p electrons in the double bond of 2m.T hus electrophilic addition of 8 to 2m leads to the formation of the iodonium ion 9.…”

Combination Catalysis in Enantioselective Trifluoromethylation

“…The mechanism of this a-trifluoromethylation of aldehydes was proposed to proceed through enamine catalysis (Scheme 6), in which the hypervalent iodine reagent could enable the C À CF 3 bond formation via an iodonium addition/ reductive elimination process. [26] High levels of enantioinduction should be possible using catalyst 10 on the basis of enamine olefin geometry control and selective Si-facial exposure (via benzyl shielding of the Re face of enamine intermediate).…”

Mild Silver‐Mediated Geminal Difluorination of Styrenes Using an Air‐ and Moisture‐Stable Fluoroiodane Reagent

“…[26] Accordingly, our plausible mechanism (Figure 1) involves silver-activated addition of the iodane to the double bond of [D 2 ]-2 a to give the iodonium ion 6. Togni and co-workers [27] studied the activation of the CF 3 analogue of 1 using zinc salts.…”