Stereospecific synthesis of naturally-occurring 4-alkylideneglutamic acids, 4-alkylglutamates and 4-alkylprolines 1
作者:Claire M. Moody、Douglas W. Young
DOI:10.1039/a703489j
日期:——
Three of these have been converted to the 4-alkylideneglutamic acids, 1, 2 and 3, which are identical to known natural products, the synthesis confirming 2 and 3 as the E-isomers. Catalytic reduction of the 4-alkylidenepyroglutamate derivatives 8 is stereospecific and affords an effective route to (2S,4S)-4-alkylglutamic acids and (2S,4S)-4-alkylprolines. Cuprate addition to the enone 5 affords access
已经发现由(2S)-焦谷氨酸制备的烯胺酮4以明显的1,4-方式与DIBAL和格利雅试剂反应,得到各种亚烷基衍生物8,除乙烯基衍生物8e外,它们是仅作为(E)异构体形成。这些中的三个已被转化为与已知的天然产物相同的4-亚烷基谷氨酸1、2和3,合成证实2和3为E-异构体。催化还原4-亚烷基次谷氨酸衍生物8是立体定向的,并提供了通往(2 S,4 S)-4-烷基谷氨酸和(2 S,4 S)-4-烷基脯氨酸。向烯酮5中加入铜酸盐可以进入(2 S,4 R)-差向异构体15,而卡宾的加入使得可以制备环丙基谷氨酸32和33。