ChemInform Abstract: Selective Oxidations of Activated Alcohols in Water at Room Temperature.

Abstract

Selective Oxidations of Activated Alcohols in Water at Room Temperature. -Secondary allyl alcohols are unreactive under the investigated conditions allowing the selective oxidation of primary allylic alcohols in the presence of secondary allylic substrates. The aqueous surfactant mixture can be recycled and reused for at least five runs. -(LIPSHUTZ*, B. H.; HAGEMAN, M.; FENNEWALD, J. C.; LINSTADT, R.; SLACK, E.; VOIGTRITTER, K.; Chem. Commun. (Cambridge) 50 (2014) 77, 11378-11381, http://dx.

Transitioning organic synthesis from organic solvents to water. What's your E Factor?

“…A “greener” variant has been developed, in part, where the same types of ingredients have been utilized for allylic and benzylic systems, albeit the organic solvent has been replaced by water in which nanoparticles composed of TPGS-750-M are present. 71 The source of copper was also changed to the far less expensive CuBr, driven by the fact that Cu(CH 3 CN) 4 OTf under these conditions did not afford synthetically useful levels of conversion in reasonable reaction times at 0.5 M. The Cu(II) analog, Cu(OTf) 2 · PhMe led to somewhat lower levels of product formation using model benzyl alcohol 17 (Scheme 23). Representative examples of this oxidation in water at room temperature are illustrated in Scheme 24.…”

“…Preparation of 1-methyl-1H-indole-3-carbaldehyde (18; Scheme 24). 71 To a microwave vial equipped with a stir bar was added (1-methyl-1H-indol-3-yl)methanol (80.6 mg, 0.5 mmol), copper bromide (3.6 mg, 0.025 mmol), 2,2′-bipyridine (3.9 mg, 0.025 mmol), TEMPO (3.9 mg, 0.025 mmol), N-methylimidazole (4 µL, 0.050 mmol), and 2 wt% TPGS-750-M solution in water (1.0 mL). The reaction was stirred vigorously until the starting material was consumed (TLC).…”