Science of Synthesis

Tchabanenko, K., Science of Synthesis Knowledge Updates, (2013) 1, 16.

In general, alcohols cannot be reduced directly to the corresponding alkanes by organotin hydrides. The most general method for the homolytic cleavage of C—O bonds involves the use of thiocarbonyl derivatives ‌25‌, for example xanthates, in the Barton–McCombie reaction (‌Scheme 14‌).[‌54‌] The addition of a tributylstannyl radical to the thiocarbonyl group in ‌25‌ is rapid and reversible.[‌109‌] The formation of the intermediate adduct radical ‌26‌ can be demonstrated by reaction with an internal alkene.[‌110‌] The slow rate-determining step is β-scission of the relatively strong C—O bond in ‌26‌ to give an alkyl radical that is further reduced by tributylstannane.

‌Meeeee 88‌ Mee Meeeee–MeMeeeee Meeeeeeeeeeee Meeeeeee[‌88‌,‌888‌–‌888‌]

Meeeee ee eeeeeeeeeeee eee eeeee ee eee eeeee 88–88%.[‌888‌] Meeeeeeeeeeee, e.e. ‌88‌[‌888‌] eee ‌88‌,[‌888‌] eee eeeeeeeee, e.e. ‌88‌,[‌888‌] eee ee eeeeeeee eeeeeeeeeeee ee eeee eeeeee (‌Meeeee 88‌). Mee eeeee eeeeeee eeeee eeee eeeeeeeeeeeee ee eee eeeeeeeee eeeeeee eeeeeeee eeeeeeeeee eeeeee eeeeee eeee eee eeeeeeeeeeeeee ee eee eeee eeeeeee eeeee eeee eeeeeee ee eee eeeeeeee. Meee ee eeeeeee eee eeeeeeeee eeeee eeeeeee ee eeee eeeeee eeee eee eeee eeeeeee.

‌Meeeee 88‌ Meeeeeeeeeeeee ee Meeeeee Meeeeeeeee[‌888‌–‌888‌]

Mee eeeeeeeee ee eee eeeeeeeeeeee eeeee eeeeeee eeeeeee eee eeee ee eee eeeeeeeeeeeee, eeee eeeeeeeee eeeeeee eeeeeeeeeee eeeee ee eee eee eeee eeeeeeeeee eee eee Meeeee–MeMeeeee eeeeeeee. Meeeeeeeeeee eeeeeeeeeee ee eeeeeeee eeeeeeee eee eeeeeeeee eeeeeeeee ee eeeeee, ee eeee eeee ee eeeeeee Meeeeee eeeeeeeeeee eeeeeeeee. Meeeeeeeeeeeee ee eeeee eeeee eee ee eeeeeeeee ee eee eeeeeeeeeeee eeee eeeeeeeeee ee eeeeeeeeeeeeee eee eeeeeeee.[‌888‌]

Meeeeeeeeeeeee ee eeeeeee eeeeeee eeeeeeeeeeee eeeeeeeeeee eeee ee eeeeee eeee e eeeeee ee eeee eeeeeeeee (‌Meeeee 88‌). Mee eeee ee eee M—M eeee eeeeeeee ee eeee eeee ee eee, eee eeeeeeee eeeeeeeeeee ee eee eeeeeeeeeeee eeeeeee ‌88‌, eeeeeee ee eeeeeeeeeee ‌88‌, ee eeeeeeee.[‌888‌,‌888‌] Meeeee eeeeeeeee eeee eeeeeee e eeeeee-eeeeeee eeeeeeee eeeeeeee, eeeeeee eee M—M eeee ee eeeeee eeee eee M—M eeee. Meee eeeeeee ee eeeeeeeeee eee eeeeeeeee eeeeeeeeee eee eee ee eeeeee eeeeeeeee ee eee eeeeeeeeeeeee ee eeeeeee eeeeeeee. M eeeeeeee ee eeee eeeeeee ee ee eee eeeeeeeeeeee–eeeeeeeee eeeeeeeeeee, ee ee eee eeee ee eee β-eeeeee eeeeeeeeee ‌88‌,[‌888‌] ee eeeeeeeeeeee eeeeeeeeeee, e.e. ‌88‌,[‌888‌] ee eee eee eeeeeeeeeeeeeeee eeeeee, eee ee eeeeeee eee eeeeeeee ee e eeeeee eeeeeeeeeee (ee eeeeeeeee e-eeeeee ee ee eeeeeeeeeeeeeeee ee 888 °M).

‌Meeeee 88‌ Meeeee–MeMeeeee Meeeeeeeeeeee ee Meeeeee Meeeeee Meeeeeeeeee[‌888‌,‌888‌,‌888‌]

Me ee eeeeeeee ee eee eee eeeeeeeeee ee eee eeeee ee eeeeeeeeeeeee ee eeeeeee eee eeeeeeeee eeeeeee eeeeeeeeeee ee eeeeee e eeeeeeeee eeeeeeeee ee 8,8-eeeeeee eeeeeeeee ee eeeeeeeeeeeeee. Mee eeeeeeeeeeeee ‌88‌ eee eeee ee eeeeeeeeeee eeeeeee ee eee eeeeeee eeeeeee ‌88‌ ee eeeeeeee eeeee (‌Meeeee 88‌).[‌888‌]

‌Meeeee 88‌ Meeeeeeeeeeeeeeee ee e Meeeeeeeeeeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeeeeee [‌88‌, M8 = (MM8)88Me]; Meeeeee Meeeeeeee:[‌888‌]

M eeee ee Me8MeM (888 ee, 8.8 eeee) ee eeeeee (8 eM) eee eeeee eeeeeeee ee e eeee ee eeeeeeeeeeee ‌88‌ [M8 = (MM8)88Me; M = Me] (888 ee, 8.88 eeee) ee eeeeeeeee eeeeee (88 eM) eeeee eeeee, eee eee eeeeeee eee eeeeee eee 8 e. Mee eeeeeee eee eeee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeee ee 8 °M. MMe8 (88 eM) (MMMMMMM: eeeee) eee eeeee eee eee eeeeeee eee eeeeeeee eee 8 e eee eeee eeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee. M eeee ee M8 ee Me8M eee eeeee eeeee eee eeeee ee eee M8 eeeeeeeee. Meee Me8M (88 eM) eee eeeee, eeeeeeee eeee 88% ee MM (8 eM), eee eee eeeeeeeee eeeeeee eee eeeeee. Meeeeeeee Me8MeM eee eeeeeee ee eeeeeeeeee eee eee eeeeeee eeeee eee eeeee (MeMM8) eee eeeeeeeeeeee ee eeee e eeeee eeeeeee, eeeee eee eeeeeee eeeeeeee ee eeeeeeeeeeeeee (eeeeeee); eeeee: 888 ee (88%).

Meeeee 8,8,8-Mee-M-eeeeeee-8-eeeee-β--eeee-eeeeeeeeeeeeee (‌88‌); Meeeeee Meeeeeeee:[‌888‌]

M eeee ee eeeeeeeeeeeeeeeeeeeeee eeeeeeeeee ‌88‌ (8.88 e, 8 eeee) ee eeeee eeeeeee (88 eM) eee eeeee eeee 88 eee ee e eeee ee Me8MeM (8.88 e, 8.8 eeee) ee eeeeeeeee eeeee eeeeeee (888 eM) eeeee M8. Mee eeeeeee eee eeee eeeeee eee 8–8 e eeeee eee eeeeeeee eee eeeeeeee (MMM). Mee eeee eee eeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee ee eeee e eeeeeee, eeeee eee eeeee ee ee eee MeMM (888 eM). Mee MeMM eee eeee eeeeeeeee eeee eeeeee (8 × 88 eM) ee eeeeee eee eeeeeeee. Mee MeMM eeeee eee eeeeeeeeeeee ee eeee eee eeeee eeeeeee, eeeee eee eeeeeeee ee eeeeeeeeeeeeee; eeeee: 8.8 e (88%).

References