Methanetrisulfonic Acid: A Highly Efficient Strongly Acidic Catalyst for Wagner-Meerwein Rearrangement, Friedel-Crafts Alkylation and Acylation Reactions. Examples from Vitamin E Synthesis

Abstract

Methanetrisulfonic acid had been prepared for the first time over 140 years ago, but it was used only scarcely in chemical transformations. In the course of our activities dealing with key-steps of industrial syntheses of vitamins, e.g. economically important vitamin E (acetate), we found that methanetrisulfonic acid is an extremely effective catalyst in a variety of reactions. Examples of its applications are Wagner-Meerwein rearrangements, Friedel-Crafts alkylations and ring closures, as well as acylation reactions. Use of this catalyst in truly catalytic amounts (0.04-1.0 mol%) resulted in highly selective transformations and yields over 95%. (Remark by the authors: We are describing only one example each for the various types of reactions. Therefore, it would be more appropriate to write (here and in the Introduction and in the Conclusion sections): "Wagner-Meerwein rearrangement, Friedel-Crafts alkylation and ring closure, as well as acylation reactions")

Vitamins and Nutraceuticals from the Perspective of Process Research

“…Beside other novel catalysts, [1e] strongly acidic perfluorinated imides 5 [2] and methides 6 and 7 [3] applied in true catalytic amounts delivered superior results. Other exceptionally active acidic catalysts were phosphorus acid 8 [4] and methanetrissulfonic acid 9 [5] which gave excellent results also in other transformations such as acylation and Wagner-Meerwein rearrangement reactions.…”

Large-Scale Production of Bioactive Ingredients as Supplements for Healthy Human and Animal Nutrition

“…One example is the use of methanetrisulfonic acid (easily accessible from acetone and oleum) in truly catalytic amounts (0.04-1.0 mol%), which catalyzes three different types of reactions in the synthetic route outlined in Scheme 2: 7 → 8, 10 + 6 → 2, and 2 → 11. [26] A highly selective condensation of monoacetate 9 with isophytol (6) to acetate 11 can be accomplished by carefully chosen reaction parameters, including type and amount of catalyst, preventing a considerable saponification of starting material and product. [27] Remarkably, enzyme catalysis can be used cost-effectively not only for highvalue products like enantiopure drugs, but also for the large-scale preparation of taining chiral P,N-ligands opened the way to a completely different retrosynthetic concept.…”

“…protecting against some types of cancer and cardiovascular diseases, stimulate the immune system and have beneficial effects for skin health. The most prominent carotenoids in the human blood plasma are the nutritionally most important ones, such as b-carotene (27), lycopene (26), b-cryptoxanthin, as well as (all-R)-lutein (31) and its isomer (R,R)zeaxanthin (28). The latter two occur in the human eye and are believed to reduce the risk of age-related macular degeneration (AMD), [33,34] which is a leading cause of blindness in the US and Western World.…”

Unexpected Diversity within Solid‐State Structures of Methanetrisulfonate Salts

“…Polysulfonic acids will, in general, show similar characteristics, albeit more pronounced . In this context, methanetrisulfonic acid (H 3 mts, 1 ) has been used as a potent acid catalyst for esterification, Friedel‐Crafts alkylation of phenols, ethylene hydration, Fries rearrangement of phenylacetate, and Wagner‐Meerwein rearrangement …”

“…First synthesized by Theilkuhl as early as 1868 from calcium methylsulfate and oleum, H 3 mts and its salts have been studied in detail by Bagnall and subsequently by Backer and Terpstra . Further synthetic methods to access H 3 mts include the reaction of potassium sulfite with trichloronitromethane via nitromethanedisulfonic acid, oxidation of 1‐(sulfothio)methanedisulfonic acid with bromine, reaction of potassium hydrogensulfite with diazomethanedisulfonic acid, oxidation of methanetris(thioacetate) with peracetic acid, and, as the probably most useful modern alternative, sulfonation of various acyl compounds such as acetanilide, acetic acid or its anhydride, or acetone with oleum (Scheme ).…”