Science of Synthesis

Paul Krapcho, A., Science of Synthesis, (2006) 8, 977.

When trityl ethers are treated with cerium(III) chloride heptahydrate/sodium iodide in refluxing acetonitrile, the trityl group is cleaved to afford the corresponding alcohols. This process can be selective; for example, in the cleavage of ethers ‌142‌, the 2,2-dimethyl-1,3-dioxolane unit remains intact as do a number of other groups attached through oxygen to C6 of the bicyclic system (‌Scheme 109‌).[‌267‌] The stable groups include allyl substituents, although in the case of some other allyl ethers, cerium(III) chloride heptahydrate/sodium iodide in refluxing acetonitrile effects cleavage with high chemical selectivity to the corresponding alcohols ‌143‌ (‌Scheme 109‌).[‌268‌] In the same way, the 4-methoxybenzyl ether group may also be cleaved selectively by cerium(III) chloride and sodium iodide.[‌269‌] Indeed, this methodology has been applied to a wide variety of methoxybenzyl ethers ‌144‌ to restore the alcohol function in the presence of other potentially vulnerable groups; it also works efficiently with methyl 2,4,6-tri-O-benzyl-3-O-(4-methoxybenzyl)hexopyranoside, to release the corresponding alcohol ‌145‌ in 90% yield (‌Scheme 109‌).[‌269‌]

‌Meeeee 888‌ Meeeeeeeeeee ee Meeeeeee ee Meeeeeee ee Meeee Meeeeeeeeeeee Meeeee, Meeee, eee 8-Meeeeeeeeeeee Meeeee[‌888‌–‌888‌]

Meeeeeeeeeee Meeeeeeee

8-Meeeeeee (‌888‌, M8 = 8-Meeeeeee); Meeeeee Meeeeeeee:[‌888‌]

M eeee ee eeeee 8-eeeeeeee eeeee (8.8 e, 8.8 eeee) eee MeMe8•8M8M (8.8 e, 8.8 eeee) ee MeMM (8 eM) eee eeeeeee eeee MeM (8.88 e, 8.8 eeee), eee eee eeeeeee eee eeeeeeee eee 8 e, eee eeeeeeee eeee 8 M ee MMe. Mee eeeee eee eeeeeeeeee ee eeeeeee eeeee eeeeeee eeeeeeee. Mee eeeeeee eee eeeee ee ee MM8Me8, eee eee eeee eee eeeeee eeee M8M eee eeeee (Me8MM8). Mee eeeeeee, eeeee eee eeeeeee ee eee eeeeeee, eee eeeeeeee ee eeeeee eeeeeeeeeeeeee; eeeee: 88%.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8e8, 888.
• 8.Meeeee-Meee, (8888) 8/8e8, 888.