Taming of fluoroform: direct nucleophilic trifluoromethylation of Si, B, S, and C centers.

Fluoroform (CF(3)H), a large-volume by-product of the manufacture of Teflon, refrigerants, polyvinylidene fluoride (PVDF), fire-extinguishing agents, and foams, is a potent and stable greenhouse gas that has found little practical use despite the growing importance of trifluoromethyl (CF3) functionality in more structurally elaborate pharmaceuticals, agrochemicals, and materials. Direct nucleophilic trifluoromethylation using CF(3)H has been a challenge. Here, we report on a direct trifluoromethylation protocol using close to stoichiometric amounts of CF(3)H in common organic solvents such as tetrahydrofuran (THF), diethyl ether, and toluene.

A domino approach of Heck coupling for the synthesis of β-trifluoromethylstyrenes.

A domino approach of Heck coupling was used to synthesize β-trifluoromethylstyrene derivatives from iodoarenes and 1-iodo-3,3,3-trifluoropropane in moderate to good yields. This method avoids the use of low-boiling, gaseous reagents such as 3,3,3-trifluoropropene, and additives and phosphines in the catalytic system.

A domino approach (hydrolysis/dehydrohalogenation/Heck coupling) for the synthesis of styrene sulfonate salts.

A domino approach of hydrolysis/dehydrohalogenation/Heck coupling was used to synthesize styrene sulfonate salts from iodoarenes and chloroethanesulfonyl chloride in good to excellent yields. Methodology was applicable for heterocyclic as well as disubstituted iodoarenes. Some of the key features of this synthetic methodology include the use of phosphine free catalytic system, water as an environmentally friendly solvent, short reaction times, and absence of additives.

A light-gated synthetic ion channel.

A gated synthetic ion channel with beta-cyclodextrin as the pore and azobenzene as the gate is reported. Irradiation converts a tethered trans-azobenzene to cis-azobenzene which likely transforms the channel from a self-inclusion complex to a dissociated structure. This transformation results in an increase in anion transport and a decrease in cation transport across a phospholipid vesicle membrane.

Conformational equilibria of ethanolamine and its hydrochloride in solution.

The conformational preferences of ethanolamine and its hydrochloride in solution were estimated by comparing experimental NMR vicinal proton-proton coupling constants to semiemprical coupling constants for each staggered rotamer, derived by the Haasnoot-Altona method. Strong gauche preferences are observed for both ethanolamine and its hydrochloride over a wide range of solvent polarities. Concentration was not observed to significantly affect the position of the conformer equilibria.

Simple thiazocine-2-acetic acid derivatives via ring-closing metathesis.

A new protocol for synthesis of 2-heterocylylacetic acid derivatives involving conjugate addition of allyl mercaptan to an acrylate containing a tethered olefinic site followed by RCM (ring-closing metathesis) is described. In this series, sulfanyl derivatives were unreactive, while sulfoxide and sulfone analogues provided the corresponding thiazocines in fair to excellent yields. Use of the sulfoxide oxidation state as a protecting group for sulfides inert to RCM is demonstrated also.

A redox-mediated molecular brake: dynamic NMR study of 2-[2-(methylthio)phenyl]isoindolin-1-one and S-oxidized counterparts.

A redox-mediated molecular brake based on the sulfide-sulfoxide redox cycle is illustrated by modulation of the rotation rate of an N-Ar "shaft" by varying the oxidation state of sulfur in 2-[2-(sulfur-substituted)phenyl]isoindolin-1-ones. N-Ar rotational barriers in methylsulfinyl (2) and methylsulfonyl (3) derivatives (13.6 kcal mol(-1)) are approximately 5 kcal mol(-1) higher than sulfide 1.