2- Butylthio

Dichloroquinoxaline (159) gave 2-butylthio-3-chloroquinoxalme (158) [BuSNa (1 equiv, made in situ), Bu OH, exothermic then reflux, 3h ... 

Sulfonyl Fluoride 2-Butylthio-2-fl uoro-1 -trifluoromethyl-ethene ElObj. 355 (-111- -> En)... 

Sulfonyl Fluoride 2-Butylthio-2.2-difluo ro-1 - trifl uom methvl-ct ha ne F.I0b2, 355 (Educt)... 

Scheme 8 summarizes the possibilities. Successful substitution for halogen by carbanions requires reversible addition and that sets upper limits on the reactivity of the anion, although steric effects can also favor equilibration (more-substituted equilibrate faster). As before, fluoride is a better leaving group than chloride. An example is shown in equation (16), producing methyl 2-phenyl-2-(/-butylthio)propionate (24) in 94% yield after 15 h at 25 °C. There is an important solvent effect on the rate of equilibration of the carbanions68 and the conditions chosen for these early experiments are not necessarily die best there may be room to expand the scope of useful anions by careful choice of media (less polar solvents should favor equilibration). 

Benzochinon 2-Butylthio-5-hydroxy- VII/3a, 600 Benzol 4-Methoxy-l-(methylsulfinyl-acetyl)- VII/2a, 545f., 598 Butansaure... 

Cyclopropan 2-Butylthio-l-chlor-l-phenylthio- E 7a, 746 (C12CH — SR/NaOH + En)... 

S)-3-tert.-Butyloxycarbonyl-2,2-dime thyl-1,3-oxazolidin-4-ylcarbonyl]- 302 2-[(4S/5R)-3-tert.-Butyloxycarbonyl-2,2,5-tri-methyl-l,3-oxazolidin-4-carbonyl]- 302 4-tcrt.-Butyl-2-phcnyl- 187 2-Butylthio- 294 2-Butylthio-5-cyan- 217 2-Carbonylmetallo- 150 Carboxy- 302, 304... 

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