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Please login to access the full content or check if you have access via Variation 3: Substitution Using Cesium Carboxylates Activated by Crown Ethers

DOI: 10.1055/sos-SD-008-01308

Kellogg, R. M.Science of Synthesis, (200681509.

Dimethylformamide, which has been used in reactions described in the preceding sections, is rather high-boiling, and this can provide experimental problems, especially with temperature-sensitive products. Alternative procedures have been developed in which benzene or toluene is used as solvent, and 18-crown-6 is used to solubilize and activate the cesium (and, in some cases, potassium) carboxylates.[‌54‌] This methodology may be applied in the conversion of the protected and activated β-D-galactopyranoside 39 into the protected β-D-mannopyranoside 41 via 40 (Scheme 15).[‌55‌] Other, related conversions are known.[‌56‌‌58‌]

Meeeee 88 Meeeeeeeee ee e Meeeeeeee eeee e Meeeeee Meeeeeeeee Meeee Meeeee Meeeeee[‌88‌]

Mee eee ee (eeeeeeeeeeee)eeeeeeeeeee ee e eeeeeee eeeee ee eeeeeeeee eeeeeeeeee eee eeeeeeeee eeee eeeeee eeeeeee, eeeeeeeee eeee 88-eeeee-8, ee eeeeeeeeeee ee eeeee.[‌88‌] Mee eeeeeeeee ee eeeeeeee eeeeeeee eeeeeeeeeeee eeeeeeeeee 88 (Meeeee 88) ee e eeeeeee eeeeeee. Mee eeeeeeeee eeeeeeeeeeeeeeee eeeeeeeeee ee eeeeeeee ee ee eeeeeee eeeee, eeeeeee eee eeeeeeeeeeeeeeeeeeeeee 88 eeeee 88-α-eeeeeeeeeeee eeeeeee (88) ee 88% eeeee eeeeeeee eeee e 88% eeeee ee eeeeeeeeeeee eeeeeee.[‌88‌]

Meeeee 88 Meeeeeeee ee 88-α-Meeeeeeeeeee Meeeeee Meeee Meeeee Meeeeee[‌88‌]

Meeeeee eeeeeeeeeee eeeeeeeee eeeeeeee eeeeeeeeee ee eeeeee eeeeeee eeee eeee eeee eeeeeeeeeeeeee eeeeeee ee 8-(eeeeeeeeeeeee)eeeeeeee ee eeeeeee ee eeeeeee. Mee eeeeeeeee ee ee eeeeeeeee eeeeeee eeeeeee eeeeee eee 8-(eeeeeeeeeeeee)eeeeeeee eeee eee eeeeeeeeee ee e eeee eee eeeeee eeeeeeee eeeeeee ee eeeeeeeeeee eee eeee eeeeeeeeee. M eeeeeeeee eeeeeeeeeee ee eee eeeeeeeeee ee eee eeeeeeee ()-eeeeeee eeeeeeeeeeeeeeee (88) eeee eeeeeeeeee eeeeeeee (88) (Meeeee 88).[‌88‌] Meeee eeeeee eeeeeee eee 8-(eeeeeeeeeeeee)eeeeeeee, 88% ee eee eeeeeee ee ee eeeeee eeeeee ee eeeeeeeeeee; eeee eeeeee eeeeeeee ee eeee, eeeeee MM8 eeeeeeeeeeee eeeeee.

Meeeee 88 Meeeeeeeee ee eee Meeeeeeeeeeeeeee ee Meeeeee eeee eee Meeeeeee ee Meeeeeeeee ee Mee ee Meeeee Meeeeeee eee 8-(Meeeeeeeeeeee)eeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeeee

Meeeee 8,8-Me-M-eeeeee-8,8-ee-M-eeeeeeee-β-M-eeeeeeeeeeeeeee (88):[‌88‌]

M eeeeeee ee β-M-eeeeeeeeeeeeeeeee 88 (8.88e, 8.88eeee), MeMMe (8.88e, 8.8eeee), eee 88-eeeee-8 (8.88e, 8.8eeee) ee eee eeeeeee (88eM) eee eeeeeee eee 8e ee ee, eeeee eeeee ee eeeeeeee eeeeeeee eeeee ee eeeeeeee ee MMM (eeeeee/MeMMe 8:8). Mee eeeeeee eee eeeeee eeee eee. ee MeMMM8, eee eee eeeeee eeee eeeeeeeee. Mee eeeeeee eeeee eee eeeeeeeee eeee MeMMe (8×), eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee eee M8M, eee eeee eeeee (MeMM8). Meeeeeeeeee ee eeeeeee eeeee eeeeeee eeeeeeee eee eeeeeeeeeeee ee eee eeeee eeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe 8:8) eeee β-M-eeeeeeeeeeeeeee 88; eeeee: 88%. Me eee eeeeeee eee eeeeeeee eee/ee eeeeeeeee ee eeeeeeeeeeeeeeeee eee 8e, eeeeeeee ee eeeeee ee eeeeeeeee eeeee, β-M-eeeeeeeeeeeeeee 88 eee eeeeeeee; eeeee: 88%; ee 888888°M.

(88α)-8-Meeeeeeeee-8-ee-88-ee Meeeeee (88α-Meeeeeeeeeee Meeeeee; 88):[‌88‌]

Meeeeeeeeeee eee eeeeeeeee eeee eee eeeeeeeeeeeeeeeeeeeeee eeeeeeeeee 88 ee eeeeeeeee eeee MeMM8MM8Me ee eeeeeeee. M eeee ee eee eeeee eeeeeeeeeeeeeeeeeeeeee 88 (eeeeeeee eee eeeeeeeeeeeee eee eeeeeeee), MeMMe (8.8 eeeee), eee 88-eeeee-8 (8.8 eeeee) ee eeeeeee (MMMMMMM: eeeeeeeeee) eee eeeeeeee eee 88e. Meeeee eeeeeeee 88α-eeeeeeeeeeee eeeeeee (88) eeeeeeee eeee eeeeeeeeeeee eeeeee(e) (88%); eeeee: 88%. [88α-Meeeeeeeeeee eeeeeee (88) eee eeeeeeeeee ee eeeeeeeeee ee 88α-eeeeeeeeeeee, eeeee eee eeeeeeee eeee ee eeeeeeeee eeeeee.]

(8M,8M,8M)-8-Meeeeeeee-8-eeeeeeeeeeeeeeee Meeeeeee (Meeeeeeeee Meeeeeee; 88):[‌88‌]

M 8.8M eeee ee ()-eeeeeee eeeeeeeeeeeeeeee (88; 8 eeeee), MeMMe (8 eeeee), eee MMMM (8.8 eeeee) ee eee eeeeeee eee eeeeeeee eee 8e. Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee, eee eee eeeeeee eee eeeee ee ee MeMMe. Meee eeee eee eeeeee eeee M8M, 8M MMe, eee eeeee eee eeeee (Me8MM8). Meeeeee ee eee eeeeeee eeee eee eeeee eeeeeee, eeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe 88:8 ee 8:8). Mee eeeeeee eeeeee eeeee, eeeeeeee ee eeeeeeee 88 (eeeeeeeeee ee eeeeeeeeee eeee ee eeeeeeeee eeeeee), eee, eeeeeeeeee, eeeeeeeee eeeeeeeeeeeeeeee 88 (88%); eeeee: 88%.