Formal Synthesis of Both Atropomers of Desertorin C and an Example of Chirality Transfer from a Biphenyl Axis to a Spiro Centre and its Reverse
作者:Robert W. Baker、Rekha V. Kyasnoor、Melvyn V. Sargent、Brian W. Skelton、Allan H. White
DOI:10.1071/ch99134
日期:——
crystal X-raystructural determination. The similar product(S,4S)-2-(2′,4′,6-trimethoxy-4,6′-dimethyl-1,1′-biphenyl-6-yl)-4,5-dihydrooxazole(43) was converted into(S)-1-(2,4′,6′-trimethoxy-4,6′-biphenyl-2-yl)ethanone(57) which furnished(S)-1-(2′,4′,6-trimethoxy-4,6′-dimethyl-1,1′-biphenyl-2-yl)acetamide(58) (43%) and(S)-2,7′-dimethoxy-3′,5′,6-trimethylspiro[cyclohexa-2,5-diene-1,1′-(1H)isoindole]-4-one(61)
关于对映体纯形式的 4,4',7,7'-四甲氧基-5,5'-二甲基-6,8'-双香豆素 (desertorin C) (11) 的合成,反应产物的非对映体比例2-异丙氧基-6-甲氧基-4-甲基苯基溴化镁(24)和(4S)-4-异丙基-2-(2,3,5-三甲氧基苯基)-4,5-二氢恶唑(23),介于2,4-之间二甲氧基-6-甲基苯基溴化镁(37)和(4S)-4-异丙基-2-(2,3-二甲氧基-5-甲基苯基)-4,5-二氢恶唑(36)和2,4-二甲氧基-6-之间探索了(叔丁基二甲基甲硅烷氧基)甲基苯基溴化镁(46)和恶唑(36)。最后提到的反应的主要产物转化为(S,4S)-4-isopropyl-2-(2'-hydroxymethyl-4',6,6'-trimethoxy-4-methyl-1,1'-biphenyl-6 -yl)-4,5-dihydroxazole(49),其轴向构型通过单晶