Facile synthesis of 3,4-dihydro-4,4-dimethyl-2H-pyran-2-one via palladium catalyzed terminal oxidation of 3,3-dimethyl-4-pentenoates
作者:Mariko Tanaka、Hisao Urata、Takamasa Fuchikami
DOI:10.1016/s0040-4039(00)84744-9
日期:——
Selective terminal oxidation of 3,3-dimethyl-4-pentenoates does occur under chloride-free Wacker conditions [Pd(OAc)2/O2] in AcOH to give 5-acetoxy-3,3-dimethyl-4-pentenoates (7) and their analogues (2, 8) in good yields. Successive cyclization of 7 and 8 at vapor phase pyrolysis on SiO2 affords 3,4-dihydro-4,4-dimethyl-2H-pyran-2-one (1).
在无氯的Wacker条件下[Pd(OAc)2 / O 2 ]在AcOH中确实发生3,3-二甲基-4-戊烯酸酯的选择性末端氧化,得到5-乙酰氧基-3,3-二甲基-4-戊烯酸酯(7 )及其类似物(2,8),收率很高。在SiO 2上进行气相热解时,将7和8连续环化,得到3,4-二氢-4,4-二甲基-2H-吡喃-2-酮(1)。