C₂-Symmetric Bis-sulfoxide:  A Novel Chiral Auxiliary for Asymmetric Desymmetrization of Cyclic meso-1,2-Diols

Abstract

A new heterocyclic compound, C(2)-symmetric bis-sulfoxide 1, has been found to be an efficient chiral auxiliary for asymmetric desymmetrization of cyclic meso-1,2-diols via diastereoselective acetal fission. Both (R,R)- and (S,S)-1 are readily synthesized with high optical purity via asymmetric oxidation of 1, 5-benzodithiepan-3-one (2). After acetalization of meso-1,2-diols 6a-e and a mono-TMS ether 6f with this chiral auxiliary 1, the resulting acetals 7a-f were subjected to base-promoted acetal fission upon treatment with potassium hexamethyldisilazide (KHMDS) followed by acetylation or benzylation to give the desymmetrized diol derivatives 8a-f with high diastereoselectivity. The chiral auxiliary 1 is readily removed by acid-promoted hydrolysis and can be recovered without a loss in enantiomeric excess.

The Chemistry of C2‐Symmetric Bis(sulfoxides): A New Approach in Asymmetric Synthesis

“…This was also confirmed by Tanaka et al [38] on a benzodithiepan derivative, on which the first asymmetric oxidation was not controlled by a diethyl tartrate moiety, and the second one was little controlled by the newly introduced sulfinyl group (50% de). This was also confirmed by Tanaka et al [38] on a benzodithiepan derivative, on which the first asymmetric oxidation was not controlled by a diethyl tartrate moiety, and the second one was little controlled by the newly introduced sulfinyl group (50% de).…”

“…[38,113] Thus, diols 132a and 132b were acetalized with 131 in the presence of TMSOTf and 2,6-lutidine in good yields to provide 133a and 133b (Scheme 31). [38,113] Thus, diols 132a and 132b were acetalized with 131 in the presence of TMSOTf and 2,6-lutidine in good yields to provide 133a and 133b (Scheme 31).…”

Efficient and Highly Selective Aqueous Oxidation of Sulfides to Sulfoxides at Room Temperature Catalysed by Supported Iron Oxide Nanoparticles on SBA‐15

“…[1,[4][5][6] These materials have largely found applications in heterogeneous catalysis ranging from redox (hydrogenations and oxidations) processes [1,[4][5][6][7] to C À C and C À heteroatom couplings [1,7a,8] and acidcatalysed processes. [9] The selective transformation of sulfides to sulfoxides generates high-added value compounds as starting materials and intermediates (which can subsequently transformed into valuable pharmaceuticals, agrochemicals and related compounds), granting access to industrially and biologically important synthetic organic compounds including chiral auxiliaries [10,11] as well as intermediates playing key roles in the activation of enzymes. [12,13] Several catalytic systems have been reported to be active in the oxidation of sulfides.…”

Trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as a novel and efficient reagent for selective sulfoxidation of sulfides under catalyst-free condition

“…They have also received enormous interests as chiral auxiliaries in organic synthesis [2,3], and as useful building blocks for the synthesis of biologically and medicinally active compounds, and activation of enzymes as well [4,5]. Sulfoxides have also found important applications as therapeutic agents such as cardiotonic [6], antiulcerative (proton pump inhibitor) [7], antihypertensive [8], as well as psycotonics [9], and vasodilators [10].…”