Asymmetric Synthesis of 1,2-Diamines by the Addition of Allylic Zinc and Magnesium Reagents to N,N′-Bis[(S)-1-phenylethyl)]ethanediimine
作者:Giuseppe Alvaro、Fabrizia Grepioni、Stefano Grilli、Lucia Maini、Gianluca Martelli、Diego Savoia
DOI:10.1055/s-2000-6377
日期:——
The diimine prepared by condensation of glyoxal trimer dihydrate with (S)-1-phenylethylamine underwent double addition of allylic zinc compounds (2-butenyl-, 2,4-pentadienyl-, 2-methyl-2-propenylzinc bromide) in THF generally at -78 °C, with allylic inversion. The newly formed stereocentres adjacent to the nitrogen atoms had prevalently the R configuration. Removal of the auxiliary from the secondary 1,2-diamines with concomitant hydrogenation of the C=C double bonds afforded the primary 1,2-diamines. The reaction with 3-methyl-2-butenylzinc bromide gave almost exclusively the α-amino imine from which the α-aminoaldehyde was obtained by hydrolysis. On the other hand, 3-methyl-2-butenylmagnesium chloride reacted at 0-20 °C to give the diamine with linear-chain substituents, owing to the reversibility of the organometallic addition.
由二水合的二乙醛三聚体与(S)-1-苯乙胺凝缩而得到的二亚胺在THF中通常在-78 °C下进行双重加成,与烯丙基锌化合物(2-丁烯基、2,4-戊二烯基、2-甲基-2-丙烯基溴化锌)反应,伴随有烯丙基反转。与氮原子相邻的新形成的立体中心主要具有R配置。通过去除从属基团并伴随氢化C=C双键,获得了初级1,2-二胺。与3-甲基-2-丁烯基溴化锌的反应几乎专门生成了α-氨基亚胺,经过水解得到α-氨基醛。另一方面,3-甲基-2-丁烯基氯化镁在0-20 °C下反应生成了具有线性链取代基的二胺,这归因于有机金属加成的可逆性。