Microwave-assisted benzyl-transfer reactions of commercially available 2-benzyloxy-1-methylpyridinium triflate

Abstract

Benzylation of alcohols and other substrates under thermal conditions translates smoothly from conventional heating into MW-assisted organic synthesis (MAOS). Reactions times are decreased from hours to minutes while good to excellent yields are maintained. MW heating should be considered for benzylation of high-value substrates using the title reagent.

Cooperative Application of Conventional and Microwave Heating

“…Conventionally heated experiments were originally performed using commercially available benzyloxypyridinium triflate (BnOPT) . BnOPT was developed as a reagent for making benzyl ethers from alcohols under neutral conditions using either conventional or microwave heating. Benzylation of carboxylic acids has also been reported, and analogous reagents have been developed .…”

Facile (Triazolyl)methylation of MACOS-derived Benzofused Sultams Utilizing ROMP-derived OTP Reagents

“…Utilizing reported conditions for the (triazolyl)methylation of a variety of nucleophilic species, 13a the generation of a 16-member prototype library was successfully achieved in good yield and crude purity (85–100%, 1 H NMR), demonstrating both substrate and reagent scope. With the synthesis of a 16-member prototype library, a 96-member library was designed with benzothiaoxazepine-1,1-dioxide scaffolds 1–10 and OTP 20 oligomers { 1 – 14 }.…”

“…11,12 Towards this goal, a suite of soluble, high-load ROMP-derived benzyl- and triazole- phosphates have been developed for the facile, purification-free diversification of nucleophilic small molecules. 13 ROMP-derived OTP reagents are bench stable, free flowing solids that are readily soluble in a variety of solvents to generate stock solutions, making them ideally suited for parallel synthesis. With these reagents in hand, the (triazolyl)methylation of core benzthiaoxazepine-1,1-dioxide scaffolds 1 – 10 scaled-out on the MACOS platform 14 was investigated with a suite of oligomeric (triazolyl)methyl phosphate (OTP) reagents { 1 – 14 }.…”

Development of Triazine-Based Benzylating Reagents Possessing <i>t</i>-Butyl Group on the Triazine Core: Thermally Controllable Reagents for the Initiation of Reaction

“…The O-benzylation of cholesterol 1k also afforded the corresponding ether 2k in good yields (entries 15,16). Although tertiary alcohols, such as 1l and 1m, and their ethers (2l and 2m) are known to decompose under acidic or heating conditions, 2l and 2m were obtained without decomposition using approximately stoichiometric amount of X-b (entries [17][18][19][20]. In particular, better yields were observed at 40°C, which is milder than the temperature used for Dudley reagent.…”

“…DPT-BM (X-a) has several advantages compared with other representative benzylating reagents, such as benzyl triflate (BnOTf) 13) and 2-benzyloxy-1-methylpyridinium triflate (Dudley reagent), [14][15][16][17][18] available under neutral conditions. DPT-BM (X-a) is a non-hygroscopic and stable solid, allowing its treatment under atmospheric conditions.…”