Low temperature n-butyllithium-induced [3,3]-sigmatropic rearrangement/electrophile trapping reactions of allyl-1,1-dichlorovinyl ethers. Synthesis of β-, γ- and δ-lactones
Low temperature n-butyllithium-induced [3,3]-sigmatropic rearrangement/electrophile trapping reactions of allyl-1,1-dichlorovinyl ethers. Synthesis of β-, γ- and δ-lactones
作者:Aaron Christopher、Dahniel Brandes、Stephen Kelly、Thomas G. Minehan
DOI:10.1039/c3ob41777h
日期:——
Treatment of allyl-1,1-dichlorovinyl ethers with n-BuLi at â78 °C, followed by quenching with ketones, epoxides, and oxetanes, leads to highly substituted β-, γ-, and δ-lactones in good to excellent yields.
[reaction: see text]. Upon treatment with n-BuLi at low temperatures, a variety of allyl 1,1-dichlorovinyl ethers 2 undergo rearrangement to furnish gamma,delta-unsaturated esters 3 after alcohol addition. Compounds containing quaternary centers (3e: R1 = H, R2, R3 = -(CH2)5-; 3f: R1 = H, R2 = CH3, R3 = (CH2)2CH(CH3)2) may be formed in high yield and under mild conditions utilizing this protocol. The