Surnn?ury: 3,6-Dihydro-ZH-pyrans and other, cyclic or acyclic, homoallyl ethers undergo smooth ring-opening through B-elimination when treated with lithiwn diisopropylamide in the presence of catalytic amounts of potassium tert-butoxide. ... In the course of a systematic study of heteroatom effects on kinetic CH-acidities we have recognized two competing pathways for the reaction of 4-methyl-3,6-dihydro-2H-pyran ... Cl1 with organometallic reagents . While ...
