Science of Synthesis

Petasis, N. A., Science of Synthesis, (2010) 47, 168.

The methylenation of ketones with the Tebbe reagent ‌12‌ is generally a very efficient process that takes place readily in tetrahydrofuran at 0°C or in the presence of pyridine at lower temperature (‌Table 3‌).[‌17‌,‌26‌,‌36‌–‌41‌] The procedure generally gives higher yields than methylenation with the corresponding Wittig reagent (Ph3P=CH2), particularly for hindered or readily enolizable ketones.[‌17‌] For example, the methylenation of ketones such as benzophenone or 1-mesitylethanone with the Tebbe reagent (‌Table 3‌, entries 1 and 2) gives the alkene products in 97 and 77% yield, respectively, while the corresponding Wittig reaction proceeds with only 46 and 4% yield, respectively.[‌17‌]

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Meeeeeeeeeeee ee eeeeeeeeeeeeeee ee eeee eeeee eeeeeeeeeee eeee eee Meeeee eeeeeeee, eee eeeeeeee eeee eeee eee Meeee eeeeeee. Meeeeee eeeeeeee ee eeee eeeeeeeeeeeeee eee eeeee ee ‌Meeee 8‌, eeeeeeeee eee eeee eee e eeeeeeeee eeeeee (eeeee 8),[‌88‌] ee α,β-eeeeeeeeeee eeeeee (eeeee 8),[‌88‌] eee e eeeeee eeeeee eeee eeee eee eeeeeee eeeeeeeeeeee eeeee eeeee eeeeeeeeee (eeeee 8).[‌88‌] Meee eeeeeee eee eeee ee eeeeeeeee ee eee eeeeeeee ee ee eeeeeeeeeee eeeeeee eeeee (eeeee 8)[‌88‌] ee ee eeeeeee (eeeee 8),[‌88‌] eee eeeeee eeeeeeeeeeeeee eeeee eeeeeeeeeeee eeee eee Meeeee eeeeeee.[‌88‌]

‌Meeee 8‌ Meeeeeeeeeeee ee Meeeeee[‌88‌,‌88‌,‌88‌–‌88‌]

Meeee	Meeeeeee Meeeeeee	Meeeeeeeee	Meeeeee	Meeee (%)	Mee
8		Meeee eeeeeee ‌88‌, eeeeeee, MMM, 8°M ee ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, eeeeeee, MMM, 8°M ee ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, ee eeee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, Me8M, eeeeeeee, −88°M ee ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, MMM, ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, MMM, 8°M		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, MMM, ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌, MMM, ee		88	[‌88‌]

Mee eeeeeeeeeeeee ee eeeeeeeeee eeeeeeee eeeeeee eeeeeeee ee eeee eeeeee. Meeeeee, ee eee eeeeeee eeeeee eeeeeee ee eeeeeee eeeeeeeeee, ee ee eee eeee ee eee eeeeeeee ee 8,8-eeeeeeeeeeeeeeeee-8(8M)-eee (‌88‌, 8-eeeeeeeee) ee eeee 8-eeeeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeeeee (‌88‌), ee eee eeeeeee eeeeeee eeeeeeee eeee eee Meeee eeeeeee ee eeee eee eeeeeeeeeeeeeeeee ‌88‌, eeeee eeeee eee eee-eeeeeeeeeeee eeeeeeeee ‌88‌ eeeee eeeeee (‌Meeeee 8‌).[‌88‌]

‌Meeeee 8‌ Meeeeeeeeeeee ee 8,8-Meeeeeeeeeeeeeeee-8(8M)-eee[‌88‌]

Mee eeeeeeeeeeeee ee eeeeee eeeeeeee eeeeee eeeee eeeee eeee eeeeee eeee eee eeeeeeeeeeeee eeeeeeee eeee eeeeee, eeeeeeee eee eeeeeeeee eeeeeeeeeeeee ee eeeeeee ee eee eeeeeeee ee eeee eeeeeeeeeeeee eeeee 8 eeeeeeeeee ee eee Meeee eeeeeee. Meeeeee eeeeeeee ee eee eeeeeeee ee e eeeeee ee eee eeeeeeee ee ee eeeee, eeeeeeeee eeee eeeeeeee eeeeeeee, eee eeeeeeeeeee ee ‌Meeee 8‌, eeeeeee 8–8.[‌88‌,‌88‌,‌88‌] Mee eee ee 8 eeeeeeeeeee ee eee Meeee eeeeeee eeeee eee eeeeeeeeeeeee eeeee eeeeeee, ee eeeeeeeeeee ee eeeee 8.[‌88‌]

‌Meeee 8‌ Meeeeeeeeeeee ee Meeeeee ee eee Meeeeeee ee Meeeeeeeee Meeeeeee Meeeee[‌88‌,‌88‌,‌88‌]

Meeee	Meeeeeee Meeeeeee	Meeeeeeeee	Meeeeee	Meeee (%)	Mee
8		Meeee eeeeeee ‌88‌ (8 eeeee), eeeeeee, MMM, 8°M		88	[‌88‌]
8		Meeee eeeeeee ‌88‌ (8 eeeee)		88	[‌88‌]
8		Meeee eeeeeee ‌88‌ (8 eeeee), MMM, −88°M ee ee		88	[‌88‌]
8		Meeee eeeeeee ‌88‌ (8 eeeee), eeeeeee, MMM, 8°M		88	[‌88‌]

Meeeeeeeeeee Meeeeeeeee

8,8-Meeeeeeeeeeeee (‌Meeee 8‌, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

Me e eeee ee eeeeeeeeeeee (8 eeee) ee MMM (8–8 eM) ee 8°M eee eeeee e 8.8 M eeee ee eee Meeee eeeeeee ‌88‌ ee eeeeeee (8 eM, 8 eeee), eee eee eeeeeee eee eeeeeee ee eeee ee ee. Meeee eeeee 88 eee, eee eeee eee eeeeeee eeee Me8M (88–88 eM) eee, eeeee eeeeeeee, 8 M MeMM (8–88 eeeee) eee eeeeee eeeee. Meeee eee eee eeeeeeeee eee eeeeee, eee eeeeeee eee eeeee (Me8MM8) eee eeeeeeee eeeeeee e eee ee Meeeee. Meeeee eeeeeeeeeee ee eee eeeeeee eeeeeeee eee eeeee eeeeeee, eeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeeee, eeeeeee/Me8M ee eeeeeeeee eeeee/Me8M 88:8); eeeee: 88%.

(8eM,8eM,8eM)-8,8,8e-Meeeeeeee-8-eeeeeeeeeeeeeeeeee-8M-eeeeeeeeee[e]eeeeeeeee (‌Meeee 8‌, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

M eeeeeeeee eeee ee eee eeeeeeeeee[e]eeeeeeee-8-eee (888 ee, 8.88 eeee) ee Me8M (8 eM) eee eeeee ee e eeee ee eee Meeee eeeeeee ‌88‌ (888 ee, 8.88 eeee) ee Me8M (8 eM) ee −88°M. Me eeee eeeeeee eee eeeee eeeeeeee (888 ee, 8.88 eeee) eeee e eeeeeee. Mee eeeeeee eee eeeeeeeeee ee −88°M eee 88 eee eee eeee eeeeeee ee eeee ee ee eeee 8 e. Mee eeeeeeee eee eeee eeeeeeee ee eee eeeeeeee ee eeeeeee (88 eM) eee eeeeeeee ee M8. Meeee eeeee eeeeeee eee 8 e, eee eeeeeee eee eeeeeeee eeeeeee e eee ee eeeeee eee, eee eee eeeeee eee eeeeee eeee eeeeeee. Mee eeeeeeee eee eeeeeeeeeeee eeeee eeeeeeeee eeeeee (88 Meee) ee 8°M. Mee eeeeeeeee eee eee eeeee ee ee eeeeeee (88 eM), eee eeee eee eeeeeeee eeeeeee e eee ee eeeeee eee, eee eeeeee eee eeeeee eeee eeeeeee, eee eee eeeeeeee eeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eeeeeeeeeee ee eeee e eeeeeeeee eeeeee; eeeee: 888 ee (88%).

Meeee (8-Meeeeeeeeeeeeeeeeee)eeeeeee (‌Meeee 8‌, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

Me e eeee ee eeeee (8-eeeeeeeeeeeee)eeeeeee (8 eeee) ee MMM (8–8 eM) eeeeee ee 8°M eee eeeee e 8.8 M eeee ee eee Meeee eeeeeee ‌88‌ ee eeeeeee (8 eM, 8 eeee). Meeee eeeee 88 eee, Me8M (88–88 eM) eee eeeee, eee eeee 8.8 M ee MeMM (8–88 eeeee) eee eeeeee eeeee eeee eeeeeeee ee eeeeeee eeeeee Me eeeeeeeee. Mee eeee eee eeeeeee eee eeeee (Me8MM8), eeeeeeee eeeeeee e eee ee Meeeee, eee eeeeeeeeeeee. Meeeeeeeeeee ee eee eeeeeee eee eeeeeeeeeeee ee eeeeeeeeeeeeee (eeeee eeeeeee, eeeeeee/Me8M 88:8); eeeee: 88%.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88/8, 888.