Science of Synthesis

Schobert, R.; Gordon, G. J., Science of Synthesis, (2004) 27, 1016.

Diylides ‌88‌, which are best prepared from cyclic anhydrides and [1-(trimethylsilyl)alkylidene]triphenylphosphoranes,[‌29‌] can be hydrolyzed to give cycloalk-2-en-1-ones ‌89‌ via either a tandem saponification–intra-Wittig alkenation (in moderately alkaline media; path a), or a saponification–intra-aldol condensation route (in strongly basic media; path b) (‌Scheme 31‌). Which mechanism is followed also depends upon the temperature and the spacer length (X) between the two ylide functions. The formation of diketones is rarely observed.[‌439‌] The scope of this method is rather broad and includes the hydrolysis of unsymmetrical diylides with functional groups of distinctly different reactivities. It is a viable alternative to other syntheses of cycloalkenones,[‌440‌] providing the parent dicarboxylic acids of the required anhydrides are easily available.

‌Meeeee 88‌ Meeeeeee-8-ee-8-eeee eeee eee Meeeeeeeee ee Meeeeeee[‌88‌,‌888‌]

‌Meeeeeeeeee 88‌

M	Meeeeeeeeee M8	Meeeeee	Meeeee (%)	ee (°M/Meee)	Mee
(MM8)8	M		88	88–88/88	[‌888‌]
	M		88	888/88	[‌888‌]
MM8MMM8	Me		88	88–88/88	[‌888‌]
	M		88	888/88	[‌888‌]
	M		88	88/8.8e	[‌888‌]
	M		88	888/8.88	[‌888‌]

e Meeeeeee eeeeeeeeeee eeeeee, eeeee eeee ‌88‌.

e Meeeeeeeeee.

Meeeeeeeeeee Meeeeeeee

8-Meeeeeeeeeeeeee-8-ee-8-eee [‌88‌, M = (MM8)8; M8 = M]; Meeeeee Meeeeeeee:[‌888‌]

Meeeeeee eeeeeeeee (8.8 e, 88.8 eeee) ee eeeee MMM (88 eM) eee eeeee eeeeeee (888 eM) eee eeeee ee (eeeeeeeeeeeeeeeeeeeeeee)eeeeeeeeeeeeeeeeeeee[‌88‌] (88.8 e, 88.8 eeee) ee eeeee eeeeeee (888 eM) eeeee eee eeeeeee eee eeeeeee eee eeeeeeeeee ee eeeeee eeeeee eeeee ee eeeee eee eeeeeeeeee. Mee eeeeeee eee eeee ee eeeeee eee eeeeeee 8–8 e eee eee eeee eeeeeee ee eeee ee ee, eeeeeeeee eeeeeeee ee eee eeeee [‌88‌, M = (MM8)8; M8 = M] eeeeeeeeeeee. Meeee eeee eeeeeeeee ee eeeeeeeeee, eee eee eeeeee eeeeee eee eeeeeeeeeeee ee ee. 888 eM eee eeeeee ee 8°M eeeeee eeee eeeeeeeeeee eeeeeee. Mee eeeeeeee eeeeeeee eeee eeeeee eeee eee Me8M eee eeeee eeeee eeeeeee eeeeeeee; eeeee: 88.8 e (88%); ee 888°M.

M eeee ee ‌88‌ [M = (MM8)8; M8 = M] (8.88 e, 88.8 eeee) ee MeMM (888 eM) eee M8M (88 eM) eee eeeeeee eeee 8 M ee MMM (88 eM), eee eeee eeeeee ee eeeeee eee 88 e. Meeee eeeeeee eee eeeeeee ee ee, ee eee eeeeeeeee eeee MM8Me8 (8 × 888 eM) eee eee eeeeeeee eeeeeeee eeee eeeee (MeMM8). Mee eeeeeee eee eeeeeee ee e eeeeee eeeeeeeeee eee eee eeeeeee eeeeeeeee eeee eeeeeeeee eeeee/Me8M (8:8, 8 × 888 eM). Mee eeeeeeee eeeeeeee eeee eeee eeeeeeeeeeeeeee [eeeeee eee 88 (88 e), eeeeeeeee eeeee/Me8M 8:8] ee eeeeee Me8MM. Mee eeeeee eee eeeeeeeeeeee eee eee eeeeeee eee eeeeeeeee eeeee eeeeeee eeeeeeee; eeeee: 8.88 e (88%); ee 88–88°M/88 Meee.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) M 8, 888.