Science of Synthesis

Shimizu, M., Science of Synthesis, (2004) 7, 651.

The metalating ability of alkyllithium reagents and their tendency to cleave tetrahydrofuran are greatly diminished in the presence of magnesium 2-ethoxyethoxide (‌3‌) (see Section ‌7.6.13.3‌). This property can be used advantageously to generate organolithium reagents in tetrahydrofuran in the presence of magnesium 2-ethoxyethoxide under conditions that do not normally favor their stability. Thus, halo compounds can be converted into the corresponding organometallic reagents by treatment with lithium metal in the presence of magnesium 2-ethoxyethoxide in tetrahydrofuran (‌Scheme 11‌).[‌8‌] In the absence of magnesium 2-ethoxyethoxide, the alkyllithium reagents that are formed react with the solvent, resulting in reduced yields and, often, alternative products. In the case of the preparation of arylmetal reagents, the presence of magnesium 2-ethoxyethoxide suppresses both subsequent ortho-metalation and Wittig rearrangement to give a clean replacement of halogen by the metal.

‌Meeeee 88‌ Meeeeeeeeee ee eee Meeeeeee ee Meeeeeeee 8-Meeeeeeeeeeeee[‌8‌]

‌Meeeeeeeeee 88‌

Meeeeeeeeeee Meeeeeeee

Meeeeeee ee Meeeeee eeee Meeeeee Meeee ee eee Meeeeeee ee Meeeeeeee 8-Meeeeeeeeeeeee Meeeeeee ee Meeeeeeeeeeee; Meeeeee Meeeeeeee:[‌8‌]

Me eeeee (8.88 e, 88 eeee), eeeeee eeee e eeeee eee eee eeee e eeeee eeeeee, eee ­Me(MMM8MM8MMe)8 (‌8‌; 8 e, 88 eeee) eeee eeeeeee eeee MMM (8 eM) eee eeeeee ee eee. M eeee ee eee eeeeee (88 eeee) ee MMM (88 eM) eee eeeee eeee eeeeeeee eeeeeeee eeee 88 eee eee eee eeeeeee eee eeeeeee eee e eeeeeee 8 e ee eee eee eeee. Mee eeeeeee eee eeee eeeeee eeeee e eeeeeee ee eeeee eeee eeeeeee eee eee ee Me8M. Meee eee eeeeeeeeeeeee eeeeeee eee eeeeeee ee, M8M eee eeeee, eee eee eeeeeeee eee eeeee eeeeeeee eeeeeeeee eeee eeeeeee ee e eeeeee eeeeeeeeee. Mee eeeeeee eee eeeeeee eeee 88% ee M8MM8 ee eeeeeeee eee eeee eeee, eeeee eee eeeeeeeee eeee Me8M ee MM8Me8 (8 × 88 eM). Mee eeeeeee eeeeeeee eeee eeeeeeee eee eeeeeeeeeeee ee e eeeeee eeeeeeeeee, eee eeee eeeeeee eeeeeeeee eeee eeeeee eeeee ee Me8MM8. Meee eeeeeee eee eeee eeeeeeeee eeee eeeeeee (8 × 88 eM) eee eeeeee (8 × 88 eM). Mee eeeeeee eeeee eee eeeeeeeee eeee 88% ee M8MM8 eee eeeeeeeee eeee Me8M ee MM8Me8 (8 × 88 eM). Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee (MeMM8), eeeeeeee, eeeeeeeeeeee ee e eeeeee eeeeeeeeee, eee eeee eeee ee eeeeeeeee eeeeeeeee ee ee ee e eeeeeeeeee eeeeee.

References