Rational Design of a Metallocatalytic Cavitand for Regioselective Hydration of Specific Alkynes

Abstract

The synthesis of a functionalized supramolecular cavitand with inwardly oriented AuI and P=O moieties was explored, including its catalytic proclivity in the selective hydration of internal alkynes. The cavitand works as a supramolecular flask device: AuI coordinates to the triple bond, the P=O moiety connects with a H2O molecule, and the cavity favors folding of a single alkynyl side chain. Several tests of different substrate patterns indicated that the cavity was substrate specific, similar to enzymatic catalysis.

Evaluation of the Catalytic Capability of cis‐ and trans‐Diquinoxaline Spanned Cavitands

“…1 H NMR spectroscopy determined the chemical yields and product distribution (proportions of 7f and 7g). [11] 1 H NMR spectroscopic data for 7f and 7g were identical to those for commercially available authentic sample.…”

“…Purification by short‐plug silica‐gel column chromatography with use of a Pasteur pipette and [D 8 ]toluene as eluent gave a colorless C 7 D 8 solution. 1 H NMR spectroscopy determined the chemical yields and product distribution (proportions of 7f and 7g ) . 1 H NMR spectroscopic data for 7f and 7g were identical to those for commercially available authentic sample.…”

“…An introverted bis‐gold cavitand was efficient in the dimerization of two different terminal alkynes . Another type of gold cavitand, in which a Lewis acid gold cation was associated to a Lewis basic P=O moiety, displayed high regio‐selectivities in addition of H 2 O to unsymmetrical alkynes; for example, 3‐octanone was yielded in 91 % starting from 3‐octyne . Although the advantage of cavitand catalysis in selective transformations are obvious, yet a study of structure‐activity relationship is not obvious enough.…”

“…Diquinoxaline-spanned resorcin [4]arenes those are in cis-1, cis-2 and cis-3 and in trans-4, trans-5 and trans- 6. Lewis acid gold cation was associated to a Lewis basic P=O moiety, displayed high regio-selectivities in addition of H 2 O to unsymmetrical alkynes; for example, 3-octanone was yielded in 91 % starting from 3-octyne. [11] Although the advantage of cavitand catalysis in selective transformations are obvious, yet a study of structure-activity relationship is not obvious enough. Particularly, from the viewpoint of basic research, comprehension of mechanistic aspects awaits upgrading.…”

Capturing the Monomeric (L)CuH in NHC‐Capped Cyclodextrin: Cavity‐Controlled Chemoselective Hydrosilylation of α,β‐Unsaturated Ketones

“…Quite a few systems display the possibility to select a substrate over another, based mainly on steric hindrance around the metal induced by the cavity . A few regioselective reactions have been reported with this kind of systems where, again, the steric hindrance of the cavity governs the approach of the substrate and therefore the outcome of the reaction. Following the same approach, chiral cavities have been used to induce enantioselective reactions .…”