Synthesis of<i> C</i><sub>3</sub>-Symmetric Tris(β-hydroxy amide) Ligands and Their Ti(IV) Complex-Catalyzed Enantioselective Alkynylation of Aldehydes
作者:Tao Fang、Da-Ming Du、Shao-Feng Lu、Jiaxi Xu
DOI:10.1021/ol050047v
日期:2005.5.1
The asymmetric catalytic alkynylation of aldehydes with these new C3-symmetric chiral tris(beta-hydroxy amide) ligands and Ti (O(i)'Pr)4 was investigated. Ligand 4c synthesized from (1R,2S)-(-)-2-amino-1,2-diphenylethanol is effective for the enantioselective alkynylation of various aldehydes, and high enantioselectivity was obtained with aromatic aldehydes and alpha,beta-unsaturated aldehyde (up to
[反应:请参见文字]。通过1,3,5-苯三甲酰氯与光学纯氨基醇的反应,合成了一系列新的手性C3对称三(β-羟基酰胺)配体(产率高达96%)。研究了醛与这些新的C3对称手性三(β-羟基酰胺)配体和Ti(O(i)'Pr)4的不对称催化炔基化反应。由(1R,2S)-(-)-2-氨基-1,2-二苯乙醇合成的配体4c对各种醛的对映选择性炔化反应有效,并且芳族醛和α,β-不饱和醛可得到高对映选择性到92%ee)。