Miyabe Hideto, Fujii Kayoko, Naito Takeaki
Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan.
Org Biomol Chem. 2003 Jan 21;1(2):381-90. doi: 10.1039/b208823a.
The diastereoselective alkyl radical addition to chiral oxime ethers was studied with a view to preparing enantiomerically pure alpha,beta-dialkyl-beta-amino acid derivatives. The phase transfer-catalyzed alkylation of Oppolzer's camphorsultam derivative of oxime ether proceeded smoothly to give the alkylated N-(beta-oximino)acyl derivatives. In the presence of BF3.OEt2, radical addition to the oxime ethers proceeded using triethylborane as the radical initiator to give alpha,beta-dialkyl-beta-amino acid derivatives with excellent diastereoselectivity.
为了制备对映体纯的α,β-二烷基-β-氨基酸衍生物，研究了向手性肟醚进行非对映选择性烷基自由基加成反应。肟醚的Oppolzer樟脑磺内酰胺衍生物的相转移催化烷基化反应顺利进行，得到烷基化的N-(β-肟基)酰基衍生物。在BF3·OEt2存在下，以三乙基硼烷作为自由基引发剂，肟醚发生自由基加成反应，得到具有优异非对映选择性的α,β-二烷基-β-氨基酸衍生物。
