SNAAP Sulfonimidate Alkylating Agent for Acids, Alcohols, and Phenols

Abstract

Stable,fonimidate has been prepared in high yield by direct O-ethylation of N-tert-butyl-4-nitrobenzenesulfonamide with iodoethane and silver(I) oxide in dichloromethane. This sulfonimidate directly ethylates various acids to esters; the stronger the acid, the faster it alkylates and in higher yield. It readily ethylates alcohols and phenols to ethers at room temperature in the presence of tetrafluoroboric acid catalyst without molecular rearrangements or racemization. We have defined these reactions as SNAAP alkylations: [substitution, nucleophilic of acids, alcohols and phenols]. The hard sulfonimidate alkylating agent is chemoselective, preferring oxygen > nitrogen > sulfur. The sulfonamide byproduct of alkylation is readily recycled to the sulfonimidate.

Highly Chemoselective NH- and O-Transfer to Thiols Using Hypervalent Iodine Reagents: Synthesis of Sulfonimidates and Sulfonamides

“…This has led to application as sulfoximine precursors on reaction with organometallics, and in materials science as monomers for polymerization . They are also reactive by S N 2 at the alkoxy carbon with the sulfur group as an effective leaving group affording a sulfonamide. , …”

Synthetic approaches and applications of sulfonimidates

“…In 2013, the same author exploited the application of their sulfonimidate rearrangements, utilizing them as alkyl transfer reagents to a range of acids, alcohols and phenols. 17 Utilizing nitro-containing sulfonimidate 38, the ethylation of acids to esters was achieved without a catalysthowever, the reaction required catalytic amounts of fluoroboric acid-dimethyl ether complex (10 mol%) for the conversion of alcohols and phenols to ethers (yields up to 94%, Scheme 10). For each reaction con-ducted, the side product isolated was the resulting sulfonamide 39 from the sulfonimidate reagent.…”

“…Aside from their most prominent application as building blocks to access alternative sulfur(VI) compounds, sulfonimidates have found uses as alkyl transfer reagents to acids, alcohols and phenols, 17 playing on the lability of sulfonimidates under acidic conditions (also noted by ). 1 In addition to their acid sensitivity, they are also susceptible to elevated temperatures, being converted into sulfonamides over extended periods of time.…”