Conformationally rigid acyclic 2,2,6,6-tetramethyl-3,5-heptanediol (TMHDiol) derivative as a new class of chiral auxiliaries
作者:Ichiro Suzuki、Hirofumi Kin、Yoshinori Yamamoto
DOI:10.1021/ja00075a032
日期:1993.11
As a new chiral auxiliary, a 2,2,6,6-tetramethyl-3,5-heptanediol (TMHDdiol) derivative has been developed. The chiral auxiliary is an acyclic, but strongly conformationally biased, molecule. Conjugate addition of lithium N-benzyl-N-(trimethylsilyl)amide (LSA) to the enoates having a TMHD auxiliary proceeded with high diasteroselectivities to give β-amino esters in high yields, although the use of conventional
作为一种新的手性助剂,2,2,6,6-四甲基-3,5-庚二醇(TMHDdiol)衍生物被开发出来。手性助剂是一种无环但构象强烈偏向的分子。N-苄基-N-(三甲基甲硅烷基)酰胺锂(LSA)与具有 TMHD 助剂的烯酸酯进行共轭加成,以高非对映选择性得到 β-氨基酯,尽管使用常规助剂如-8-苯甲基和恶唑烷酮导致低非对映选择性。添加到 TMHD 巴豆酸酯、庚酸酯和肉桂酸酯中的有机铜共轭物产生了高非对映选择性,并且在 TiCl 4 存在下,TMHD 丙烯酸酯与环戊二烯的 Diels-Alder 反应提供了一种具有高非对映选择性的内加合物。LSA 的添加是通过烯酸的 s-cis 构象进行的,