Asymmetrische Diels-Alder-Reaktionen von chiralen Isoprenylethern mit reaktiven Dienophilen
作者:Roland Thiem、Klaus Rotscheidt、Eberhard Breitmaier
DOI:10.1055/s-1989-27405
日期:——
Asymmetric Diels-Alder Reactions of Chiral Isoprenyl Ethers with Reactive Dienophiles The chiral alcohols 2 react with 3-ethoxy-2-methylacrolein (1) to yield chiral 3-alkoxy-2-methylacroleins 3, which are transformed to the chiral isoprenyl ethers 5 by Wittig methylenation in good yields. 1,3-Dienes 5 undergo [4+2] cycloadditions with reactive dienophiles such as maleic anhydride (6) or 4-phenyl-4H-1,2,4-triazol-3,5-dione (PTAD, 8) to afford the chiral cycloadduct 7 and 9 in moderate to good yield and diastereomeric excess. The resolution of the racemic alcohol trans-2-mesitylcyclohexanol 2d is reported.
手性异戊烯基醚与反应性二烯烃的不对称 Diels-Alder 反应 手性醇 2 与 3-乙氧基-2-甲基丙烯醛 (1) 反应生成手性 3-烷氧基-2-甲基丙烯醛 3,然后通过 Wittig 甲烯化反应生成手性异戊烯基醚 5,收率很高。1,3-二烯 5 与马来酸酐(6)或 4-苯基-4H-1,2,4-三唑-3,5-二酮(PTAD,8)等活性二烯烃发生[4+2]环加成反应,得到手性环加成物 7 和 9,收率中等至良好,非对映过量。报告了反式-2-甲苯甲基环己醇 2d 外消旋醇的解析。