Microwave-assisted dehydration-oxidation of β-bromo-tert-alcohols to afford 2,3-unsaturated ketones in good yield is reported. The reaction of substrates with DMSO in 1:1 ratio (w/v) is promoted by ZnS in a solvent-free condition. A concurrent bi-functional activation of trans-vicinal bromo- and hydroxyl groups with ZnS is elucidated. This is a new observation under microwave and applies to β-bromo-tert-alcohols derived from 1,4-disubstitued-1-cyclohexenes. It is very useful in the synthesis of 2,3-unsaturated ketones derived from monoterpenes which are valuable flavour compounds.
报告了在微波辅助下,将β-
溴-叔醇脱
水-氧化以良好产率生成2,3-不饱和酮的研究。采用
DMSO与底物按1:1比例(
水/体积)反应,在无溶剂条件下,由ZnS催化。阐明了ZnS对顺-邻二
溴和羟基的双功能激活。这是在微波下的新发现,适用于从1,4-双取代-1-
环己烯衍生的β-
溴-叔醇。这在合成来源于单萜的2,3-不饱和酮中非常有用,而单萜是珍贵的
香料化合物。