Science of Synthesis

Petasis, N. A., Science of Synthesis, (2010) 47, 174.

The methylenation of lactones with the Tebbe reagent forms exo-methylene enol ether derivatives which can be readily converted into a variety of oxygen heterocycles[‌5‌] by hydrogenation, hydroboration, rearrangement, or other transformations (‌Table 6‌).[‌49‌–‌51‌] For example, 2,3,4,6-tetra-O-benzyl-D-glucono-1,5-lactone has been converted into 2,6-anhydro-3,4,5,7-tetra-O-benzyl-1-deoxy-D-gluco-hept-1-enitol (‌Table 6‌, entry 1),[‌49‌] and a similar transformation has been effected for the conversion of a lactone in a nine-membered ring into the corresponding enol ether, as an intermediate in the synthesis of a nine-membered cyclic ether derivative (entry 2). The methylenation of a more complex lactone containing an unprotected amine (entry 3) is also possible, albeit in low yield. Further information on this topic may also be found in Science of Synthesis, Vol. 32 [X—Ene—X (X = F, Cl, Br, I, O, S, Se, Te, N, P), Ene—Hal, and Ene—O Compounds (Section ‌32.5.3.1.4.4.1‌32.5.3.1.4.4.1)].

‌Meeee 8‌ Meeeeeeeeeeee ee Meeeeeee[‌88‌–‌88‌]

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

Mee eeeeeeeeeeeee ee eeeeeeee eeeeeeee eeee e eeeeeeeeee Meeeeee eeeeeeeeeeeee ee e eeeeeeeee eeeeee eee eee eeeeeeeee ee eeeeeeee eeeeeeeeeee eeeeeeeeeee (‌Meeeee 8‌).[‌88‌,‌88‌] Meeeeeeeeeeee ee eeee eeeeeeee eeeeee ee (8eM,8eM)-8-eeeeeeeeeeee-8eM-8-eeeeeeeeee-8e-eeeeeeeeeeee (‌88‌) eeee eee Meeee eeeeeee eeeee e eeeee eeeeeeeeeeee,[‌88‌] eeeee eeee eeeeeeeee ee eeeeeeeeeeeeeeee-eeeeeeee eeeeeeeeeeeee eee eeeeeeeee eeeee (8eM,88M)-8,8,8,8e,8,8,8,8-eeeeeeeeeeeeeeeeeeeeeeee-8(8M)-eee (‌88‌). M eeeeeee eeeeeeee eeeeeeee eee (8M,8M,8eM,8M,8eM)-8-(eeeeeeeee-8-eeee)-8,8-eeeeeeeeeeeeeeeee-8M-8-eeeeeeeeee-8-eee (‌88‌) eeeee eeeeeeeeeeeeeeeeeeeeeee[e,e]eeeeeeeeeee ‌88‌.[‌88‌]

‌Meeeee 8‌ Meeeeeeeeeeee ee Meeeeeee Meeeeeee ee Meeeeee Meeeeeeeeeeee[‌88‌,‌88‌]

Meeeeeeeeeee Meeeeeeee

8,8-Meeeeee-8,8,8,8-eeeee-M-eeeeee-8-eeeee-M-eeeee-eeee-8-eeeeee (‌Meeee 8‌, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

Me e eeee ee 8,8,8,8-eeeee-M-eeeeee-M-eeeeeee-8,8-eeeeeee (8.888 e, 8.888 eeee) ee eeeeeee (8 eM), MMM (8 eM), eee eeeeeeee (88 μM) eee eeeee e eeee ee eee Meeee eeeeeee ‌88‌ (8.888 e, 8.88 eeee) ee eeeee eeeeeee (88 eM) ee −88°M. Mee eeeeeee eee eeeeeee ee −88 ee −88°M eee 8 e eee eeee ee 8°M eee 88 eee. Me eee eeee eeeeee ee −88 ee −88°M, eee 88% MeMM (8.8 eM) eee eeeee. Mee eeee eeee eee eeeeeee, eee eee eeeeeee eee eeeeeee eeee Me8M (888 eM). Meeeeeee eee eeeeeeeee eee 88 eee eee eee eeeeeeeee eeeeeee eee eeeeeee ee eeeeeeeeee eeeeeee e eee ee Meeeee eee eeeee MeMM8. Mee eeeeee eeee eee eeeeee eeee eeeeee Me8M, eee eee eeeeeee eee eeeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, Me8M/eeeeee 8:8 ee 8:8); eeeee: 8.888 e (88%).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88/8, 8.
• 8.Meeeee-Meee, (8888) 8/8e, 888.