Reactions of alkyl 4-hydroxybut-2-ynoates with arenes under superelectrophilic activation with triflic acid or HUSY zeolite: Alternative propargylation or allenylation of arenes, and synthesis of furan-2-ones

Superelectrophiles: Recent Advances

“…The Vasilyev group has developed several new synthetic methodologies that utilize superelectrophilic vinyl cations. For example, ionization of 4-hydroxybut-2-ynoates using triflic acid or zeolite catalysts provide dicationic intermediates that react efficiently with arene nucleophiles [ 43 ]. The reaction of substrate 39 with p -xylene provides the furanone 40 in good yield ( Scheme 11 ).…”

Transition Metal‐Free Alkyne‐Aldehyde Reductive C−C Coupling trough Cascade Borylation/Olefin Isomerization

“…Our group recently disclosed basic ionic liquid as a superior medium for the borylation of unreactive primary propargylic alcohols in a transition metal‐free (TM‐free) manner . Based on these previous reports, we envision that γ ‐hydroxy‐ α , β ‐acetylenic esters might be generated through the addition of acetylide ion to aldehyde with further borylation under the basic condition to build vinylboronates in a cascade fashion without the use of transition metal catalyst. Interestingly, the proposed products continually undergo olefin isomerization and protodeboronation thereafter affording γ ‐keto esters in moderate yields as shown in Scheme .…”