Application of Mitsunobu Reagents to Redox Isomerization of CF₃-Containing Propargylic Alcohols to (E)-α,β-Enones

Abstract

Isomerization of CF(3)-containing secondary propargylic alcohols proceeds with excellent E selectivity by treatment with Mitsunobu reagents, tris(p-methoxyphenyl)phosphine (TMPP), and 1,1'-(azodicarbonyl)dipiperidine (ADDP) in the presence of phenol.

Radical Trifluoroacetylation of Alkenes Triggered by a Visible‐Light‐Promoted C–O Bond Fragmentation of Trifluoroacetic Anhydride

“…Traditional methods for the synthesis of CF3-enone adducts employed classical approaches based on Mannich type reactions, 35 aldol-type condensations, 36,37,38 and additionally several methods rely on rearrangements [39][40][41] (Scheme 1b). It has also been shown previously that methyl cinnamates can undergo reactions with TMSCF3 to form the corresponding CF3-enones.…”

β‐Trifluoromethyl α,β‐unsaturated Ketones: Efficient Building Blocks for Diverse Trifluoromethylated Molecules

“…To overcome this limitation, Yamazaki in 2011 reported another protocol for the isomerization of trifluoromethyl‐containing secondary propargylic alcohols 12 to the corresponding ( E )‐ α , β ‐unsaturated ketones 3 by treatment with a combination of tris( p ‐Methoxyphenyl)phosphine (TMPP), 1,10‐(Azodicarbonyl)dipiperidine (ADDP), and phenol (Scheme 2, Method 2 C). This reaction condition is suitable for wide variety of 4,4,4‐trifluorinated propargylic alcohols [20b] …”

One‐Pot Alkynylation of Azaaryl Aldehydes and Spontaneous Base‐Free Rearrangement into Enone Esters: an Autoinductive Mechanism

“…[27,28] Many other methods involving the use of transition metals such as Pd, Ru, Rh or Ir have been developed for the isomerization of propargylic alcohols to enones. [27,28] Many other methods involving the use of transition metals such as Pd, Ru, Rh or Ir have been developed for the isomerization of propargylic alcohols to enones.…”