Tagged Hypervalent Iodine Reagents:  A New Purification Concept Based on Ion Exchange through S_N2 Substitution

Abstract

The preparation of phenylsulfonate-tagged iodine(III) reagents as well as their use in a novel purification strategy for iodine(III)-promoted reactions is described. The concept is based on ion exchange and is initiated by an azide-promoted SN2-reaction at the alkyl sulfonate followed by trapping of the resulting aryl sulfonate anion with an ion-exchange resin. The concept is successfully proven for Ru-catalyzed oxidations of alcohols, the activation and glycosidation of thioglycosides, and the SuArez reaction of pyranoses.

Catalytic Version of and Reuse in Hypervalent Organo‐λ3‐ and ‐λ5‐iodane Oxidation

“…It will be interesting to investigate the reactivity pattern of phenyl‐λ 3 ‐iodanes with para carboxy groups 50. Kirschning and co‐workers developed an interesting method for recycling protocols using a tagged hypervalent aryl‐λ 3 ‐iodane 40 51…”

Potent HIV‐1 Protease Inhibitors Containing Carboxylic and Boronic Acids: Effect on Enzyme Inhibition and Antiviral Activity and Protein‐Ligand X‐ray Structural Studies

“…As shown in Scheme 2, commercially available 4-bromophenyl sulfonyl chloride 14 was treated with NaOMe in methanola t08Ct o2 38Cf or 12 ht op rovide the corresponding methyl sulfonate derivative in 62 %y ield. [31] Reactiono ft he resulting4 -bromosulfonate derivative with nBuLi in THF at À78 8Cf or 10 min followed by addition of B(OMe) 3 at À78 8C for 30 min provided boronic acid derivative 15 in 45 %y ield. Treatmento f15 with triethylamine in methanol at 60 8Cf or 24 hf ollowed by reactiono ft he resulting triethylammonium salt with thionyl chloride, heateda t8 0 8Cf or 24 h, furnished sulfonyl chloride 16 in 89 %y ield.…”

A Journey into Recent Microwave‐Assisted Carbohydrate Chemistry

“…In addition to the introduction of the thioacyl group, isothiocyanates play a pivotal role in the preparation of a broad series of functional groups, allowing, simultaneously, the covalent coupling of a fairly unrestricted variety of structures to the saccharide moiety. For a study on their particular properties, a series of N-glucosylthiocarbamates were synthesized by Yang and co-workers [12] through the reaction of glucosyl isothiocyanate (12) with mono-and dihydric alcohols and (13)(14)(15)(16) from glucosyl isothiocyanate (12).…”

“…Within iodine(III)-promoted transformations, Kirschning and co-workers [15] successfully accomplished the activation and glycosidation of thioglycoside 19 to give 20 (scheme 21.5).…”

“…Kirschning and co-workers [15] introduced a new concept for scavenging aryliodo species which result as by-products of iodine(III)-promoted transformations. This concept was successfully proven for the Suárez reaction of the pyranoses 76 and 78 which involves a radical β-fragmentation to give 77 and 79 (scheme 21.24).…”