Science of Synthesis

Margaretha, P., Science of Synthesis, (2009) 48, 452.

Acyl derivatives of thiohydroxamic acids are a convenient source of carbon-centered radicals.[‌61‌,‌62‌] The most commonly used compound here is N-hydroxy-2-thiopyridone (‌45‌). Its easily available acyl derivatives, e.g. ‌46‌, lend themselves to the facile production of alkyl radicals either by heating to 80°C in the presence of tributyltin hydride and 2,2′-azobisisobutyronitrile, or better, by irradiation with a tungsten lamp at room temperature in the presence of 2-methylpropane-2-thiol.[‌63‌] The overall reductive decarboxylation, which is also called the Barton reductive decarboxylation (‌Scheme 23‌) is a radical-induced chain reaction, in which a stannyl or thiyl radical adds to the sulfur atom of acyl compound ‌49‌ with concomitant cleavage of the N—O bond. The newly formed acyloxy radical decarboxylates to an alkyl radical, which in turn is trapped by the stannane or thiol to afford the (decarboxylated) alkane compound.[‌64‌–‌66‌] More recently, both tris(trimethylsilyl)silane in combination with triethylborane,[‌67‌] or tris(trimethylsilyl)methane in combination with 2,2′-azobisisobutyronitrile,[‌68‌] have been proposed as “tin-free” reducing agents.

‌Meeeee 88‌ Meeeee Meeeeeeee Meeeeeeeeeeeeee ee M-Meee-M-eeeeeeeeeeeeeeeeeeeeee[‌88‌–‌88‌]

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Meeeeeeeeeee Meeeeeeee

Meeeeeeeeee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

Meeeeeeeeeee eeeeeeee (8 eeee) ee eeeeeee (8 eM) (MMMMMMM: eeeeeeeeee) eee eeeee ee e eeeeeee, eeeee eeeeeeeeee ee eee eeeeeeeeeeee eeeeeeeee eeeeee eeee ee ‌88‌ (8.8 eeee) eee MMMM (8.8 eeee) ee eeeeeee (88 eM) ee eeeeee. Meeee 88–88 eee ee eeeeee, Me8MeM (8 eeee) eee MMMM (88–88 ee) ee eeeeeee (8 eM) eeee eeeee eeeeeeee eeee 88 eee. Meeee eeeeeeeeee ee eee eeeeeeee, eee eeeeeee eee eeeeee ee ee eee eeeeeee eeee MMe8 (88 eM) (MMMMMMM: eeeee) eee 8 e. Meeeeeeeeeee, eee eeeeeee eee eeeeeeeeeeee ee eeeeeee, eee eee eeeeeee eee eeeeeeeeee eeeeeee eeeeeeeee ee e eee-eeeee eeeeee eeee eee eeeeeeee ee e eee. eeee ee M8 ee MM8Me8 (88 eM) eee eee. ee MM (88 eM). Mee eeeee eeeeeeeee eeeeeeeeeee eee eeeeeeee eeeeeee Meeeee eee eeeeee eeee MM8Me8. Mee eeeeeeee eeee eeeeeeee eeee eee eeeeeee, eee eeeee eeeeeeeeeee, eee eeeeeee eeeee eee eeeeeee eeeeeeeee eeee MM8Me8 (8 × 88 eM). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee 8 M Me8M8M8, M8M, eee eeeee, eeeee (Me8MM8), eeeeeeee, eeeeeeeeeeee ee eeeeeee, eee eeee eeeeeeee ee Meeeeeeee eeeeeeeeeeee; eeeee: 88%.

Meeeee (‌88‌):[‌88‌]

MMMMMMM: Meeeeee eeeeeeee eeeeee eeeeeeeee eeee eeeee eeeeeeeee eeeee eeeeeee ee eeeeeeeee eeeee. Me ee eeeeeeeee eeeeeeeeeee ee eee eeeeeee.

Meeeee-8,8-eeeeeeeeeeee eeee (88.8 e, 88 eeee) eee eeeeeeeee ee eeeeeeeeeeee eeeeeee MMMe8 (88 eM) eeeee M8 ee e 888-eM eeeee-eeeeee eeeee eeee eee eeeeeeee eeee e eeeeee eeeeeeeee eee e eeeeeeee M8 eeeee. Mee eeeeeeeeee eee eeeeeee eee eeeeeeee eee 8 e. Meeeee eeee eeeeee eee eeeeee eeeeeeeee eeeeeeeeee. Mee eeee eee eeeeee ee ee, eee eeeeee MMMe8 eee eeeeeee ee ee (MMMMMMM: ee eee eeee) eeeee eeeeeee eeeeeeee (8–88 Meee) ee eeeee e eeeee eeeeeeeeeee eeeeeee ee eee(eeee eeeeeeee). Meeeee ee MMMe8 eeee eeeeeee ee eeeeeee eeeeeee. Mee eeeeeeee eeeee eee eeeeeeeee ee eeee (88°M) MMM (88 eM). M eeeeeeeeee ee eee eeeeee eeee ee ‌88‌ (88 e, 8.88 eee) ee eee MMM (888 eM) eeee eeeeeeeee eeeeeee eeeeeeeee e-MeMM (88 e, 8.88 eee) eee e eeeeeeeee eeeeee ee MMMM (8.8 e) eee eeeeeeee ee e 8-M, eeee-eeeeee eeeee eeee eee eeeeeeee eeee e eeeeeeeeee eeeeeee, e M8 eeeee, e eeeeeeee-eeeeeeeeee eeeeeeee eeeeee, eee e eeeeee eeeeeeeee eeee eee eeeeeeeee eee e M8MM8 eeee (ee eeeeee eeeee) ee ee eee eeeeeee. Mee eeee-eeeeeee eeeeeeeeee eee eeeeee ee eeeeee eee eeeeeeeeeeeeee eeeeeeeeee eeee e 888-M eeeeeeee eeee eeee eee eeeee eeeeee. Mee eeee MMM eeee ee eee eeeee eeee eeeeeeee eee eeeee eeeeeeee, eeee eee eeee ee eeeeeeee eee ee eeee eee eeeeeeeee ee MM8 eee eee eeee ee eeeeee eeeeee eeee eeeee eeeeeee. Meeee 8 e, eeeee eee ee eeeeeee eeeeeee eeeeeeeee ee eee. Meeee eeeeeeeeee eeeeeeeee eee 8 e, eee eeeeee eeeeeeeee eee eeeeeeee eeee e 88-ee Meeeeee eeeeee eee eeeeeeeeeeee eeee. Meee ee eee MMM eee eeeeeeeee eeeee eeee eeeeeee ee eeeeeeeeeeee, 888 eM ee eeeeeeeeee eeeee eeeeeeeee. Mee eeeeeeeee eeeeee eee eeeeee ee ee eee eeeeeee eeee eeeeeee (88 eM). Mee eeeeeee eee eeeeee eeee eeeeeeeeee eeeeee (888 eM) eee eeee eeee 88% MMe (8 × 88 eM). Mee eeeeeeee eeeeeee eeee eee eeeeeeeee eeee eeeeeee (8 × 88 eM) eee eee eeeeeeee eeee eeeee ee eee eeee eeeeeee eeee. Meee eee eeeeee eeee eee. ee Me8MM8 (88 eM) eee eeee M8M (88 eM), eee eeee eeeeeeeeeeee ee eeeeeeeeeee eeeeeeee eeeee e 88-ee Meeeeee eeeeee eee eeeeeeeeeeee eeee. Meee eeeee 888 eM ee eeeeeee eee eeee eeeeeeeee, MeMM (88 eM) eee eeeee ee eee eeeeeee eeee. Mee eeeeeeeee eeeeeeeeee eee eeeeee ee ee, eee eeee ee −8 ee −88°M eeeeeeeee ee eeeeeeee eee eeeeeeeeeeeeeee. Mee eeeee eeeeeeee eeee eeeeeeeee, eeeeee eeee eeee MeMM (88 eM), eee eeeee (ee/88 Meee, 8.8 e); eeeee: 8.88 e (88%); ee 888–888°M.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88/8e, 888.