?-Cleavage of Bis(homoallylic) Potassium Alkoxides. Two-Step Preparation of Propenyl Ketones from Carboxylic Esters. Synthesis ofar-Turmerone, ?-Damascone, ?-Damascone, and ?-Damascenone
作者:Roger L. Snowden、Simon M. Linder、Bernard L. Muller、Karl H. Schulte-Elte
DOI:10.1002/hlca.19870700721
日期:1987.11.4
The transformation of 36 bis(homoallylic) alcohols VII to alkenones IX and Xvia β-cleavage of their potassium alkoxides VIIa in HMPA has been investigated (cf. Scheme 2). These studies have established an order of β-cleavage for 2-propenyl, 1-methyl-2propenyl, 2-methyl-2-propenyl, 1,1-dimethyl-2propenyl, and benzyl groups in alkoxides 49a–56a and have allowed a comparison between the β-cleavege reaction
已经研究了在HMPA中通过36个双(均烯丙基)醇VII的醇钾VIIa的β裂解转化为烯酮IX和X的方法(参见方案2)。这些研究建立了醇盐49a – 56a中2-丙烯基,1-甲基-2丙烯基,2-甲基-2-丙烯基,1,1-二甲基-2丙烯基和苄基的β裂解顺序,并允许进行比较β裂解反应与烷氧化物74a – 83a中的氧化Cope重排之间的关系。作为示例性的合成应用,丙烯醛的两步制备15 –42从羧酸酯中描述,用合成在一起AR -turmerone(48),α二氢大马酮((ë) - 71),β大马酮((ë) - 109),和β大马酮((ë) - 111)。