Practical Synthesis of Aryl Triflates under Aqueous Conditions

Abstract

[reaction: see text] A practical and efficient synthesis of aryl triflates under biphasic basic aqueous conditions is described. The current methodology provides entry into these valuable substrates that omits the use of amine bases and allows facile isolation by simple solvent evaporation after phase separation. Good yields can also be obtained without the use of organic solvent.

A new method proposed for the determination of absolute configurations of α‐amino acids

“…As shown in Scheme 2, enantiopure α-amino acids (I) can be converted easily into their N-acyl derivatives (II) by reaction with carboxylic acid chlorides (SchottenBaumann). [22] Finally, compounds II can be cyclized by DCC to form the 5(4H)-oxazolones (III). [17a,23] The target compounds III are not entirely stable; they racemize slowly during the cyclization reaction and in CDCl 3 solution, [17b] probably via tautomerization [24] ; the prevailing enantiomer correlates stereochemically with the original α-amino acid whereas the minor one is produced by the racemization.…”

Thermo‐Responsive PNIPAAm Copolymers with Hydrophobic Spacers

“…The synthesis was carried out in a two-neck vessel under nitrogen atmosphere using the Schotten-Baumann reaction conditions. [8] The amino acids were first added to a NaOH water or ethanol solution depending on the amino acid used. The vessel was then cooled to 0 8C in an ice bath and acryloyl chloride added drop-wise while the suspension was stirred.…”

Glycoside-Based Ionic Liquids

“…As noted in Figure 5 (vide infra) the formation of the tosylates of polyhydroxylic species is a relatively simple matter. Tosyl chloride, in early efforts allowed to react in pyridine solution with hydroxylic substrates, reacts selectively with primary hydroxylic sites under aqueous conditions reminiscent of the simple Schotten-Baumann procedure for ester formation (Frantz et al 2002), as has been used for a wide range of ester preparations. The selectivity of the tosylation reaction and the ability to perform it in aqueous medium (Thomas et al 2009a) provide major advantages to this procedure, allowing facile formation of the tosylate ester and the equally facile subsequent displacement of the tosylate leaving group by an incoming tertiary amine nucleophile.…”