Superelectrophiles and the Effects of Trifluoromethyl Substituents

Abstract

Trifluoromethyl-substituted superelectrophiles were generated in superacid (CF3SO3H) and their chemistry was examined. The strong electron withdrawing properties of the trifluoromethyl group are found to enhance the electrophilic character at cationic sites in superelectrophiles. This leads to greater positive charge-delocalization in the superelectrophiles. These effects are manifested by the superelectrophiles showing unusual chemo-, regio-, and stereoselectivity in reactions.

Microporous Polymer Networks for Carbon Capture Applications

“…35 According to Olah's definition of superelectrophiles, under superacidic conditions, further protonation or protosolvation of the protonated aldehydes or ketones is possible, which leads to very reactive intermediates (superelectrophiles), that is, electrophiles of doubly electron-deficient (dipositive) nature whose reactivity significantly exceeds that of their parent monocations under conventional reaction conditions. [36][37][38] This super-electrophilic or multi-ionic intermediate can undergo successive condensation reactions with weaker nucleophiles, and thus it is possible the reaction even with deactivated aromatic rings (Scheme 1).…”

Catalytic asymmetric synthesis of CF3-substituted tertiary propargylic alcohols via direct aldol reaction of α-N3amide

“…The 7-azaindoline amide motif was easily hydrolysed under acidic conditions (Scheme 3a); the CF 3 substituent slowed down the formation of a tertiary cation at the propargylic position, 58 and the stereochemical integrity was maintained over the course of the transformation. The following treatment with TBAF afforded highly functionalized terminal alkyne 14 in good yield.…”

“…One of the unique features of this study is the production of CF 3 -containing chiral building blocks decorated by three distinct functional groups, making it possible to further derivatize the aldol products. The 7-azaindoline amide motif was easily hydrolysed under acidic conditions ( Scheme 3a ); the CF 3 substituent slowed down the formation of a tertiary cation at the propargylic position, 58 and the stereochemical integrity was maintained over the course of the transformation. The following treatment with TBAF afforded highly functionalized terminal alkyne 14 in good yield.…”

Synthesis and the biological activity of 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazin-3-carboxylic acids trifluoromethyl-substituted anilides

“…Due to its powerful electron-withdrawing properties the trifluoromethyl group is able to enhance reactivity of various electrophilic substrates and affect regioselectivity of reactions involving nucleophiles [1][2]. The presence of this substituent often allows to carry out chemical transformations easily that in its absence do not proceed even in the most rigid conditions; thus, it is widely used in modern preparative organic synthesis.…”