反应详情

The necessary aldehyde was obtained by an analogous procedure to that described in connection with Example 19 starting from 4-(methylthio)phenol which was converted to ethyl 2-methyl-2-(4-(methylthio)phenoxy)propionate [oil, 20% yield; NMR: 1.25(3H,t J=7 Hz), 1.6(6H,s), 2.45(3H,s), 4.25(2H,q J=7 Hz), 6.75-7.2(4H,m)]. This ester was oxidised with m-chloroperbenzoic acid in dichloromethane at ambient temperature to give, after conventional work-up, ethyl 2-methyl-2-(4-methylsulphonylphenoxy)propionate [oil, slowly solidifying: 92% yield; NMR: 1.25(3H,q J=7 Hz), 1.65(6H,s), 3.0(3H,s), 4.25(2H,q J=7 Hz), 6.9-6.95(2H,m), 7.8-7.85(2H,m)] which was then reduced with DIBAL to give 2-methyl-2-(4-methylsulphonylphenoxy)propanal as a solid (66% yield); NMR: 1.5(6H,s), 3.05(3H,s), 6.9-7.0(2H,m), 7.8-7.9 (2H,m), 9.8(1H,s).

1. customto give