Activation of H₂O₂ by Chiral Confined Brønsted Acids: A Highly Enantioselective Catalytic Sulfoxidation

Abstract

Confined chiral Brønsted acids are shown to catalyze asymmetric oxidations of sulfides to sulfoxides with hydrogen peroxide. The wide generality and high enantioselectivity of the developed method compare even to the best metal-based systems and suggest utility in other asymmetric oxidations.

Sulfoxidation inside a C3-Vanadium(V) Bowl-Shaped Catalyst

“…The right balance between rigidity and flexibility and the existence of an open hydrophobic pocket promote the accommodation of the hydrophobic sulfides near the active site and facilitate to a large extent the release of the hydrophilic sulfoxides, 4,12 while the preserved chiral microenvironment of the cavity gives rise to the observed asymmetric induction. 24 …”

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

“…The new imidophosphoric acid still bears the double functionality, acid and base, on the two phosphates, allowing small and unhindered molecules to enter the active pocket and to be activated in such a peculiar environment towards the chemical transformation. This pioneering work paved the way to other enantioselective transformations, such as sulfoxidation and acetalisation, verifying further the potential of confined BA [86,87].…”

Phosphoric Acid Catalyzed Desymmetrization of Bicyclic Bislactones Bearing an All‐Carbon Stereogenic Center: Total Syntheses of (−)‐Rhazinilam and (−)‐Leucomidine B

“…The cis stereochemistry of the bicyclic ring system was determined by X-ray crystal structure analysis. [15,16] Initial experiments on the desymmetrization of 12 a using methanol (2.0 equiv) as a nucleophile in the presence of a chiral phosphoric acid (0.1 equiv; Figure 3) gave very promising results (Table 1, entries 1-5). Reaction of 12 a with MeOH (2.0 equiv) at room temperature in the presence of TRIP 13 e (0.1 equiv) afforded the monoacid 2 a in 95 % yield with an e.r.…”