Asymmetric synthesis of O-alkylated tetronic acid derivatives via an organocatalytic Mannich reaction and subsequent intramolecular cyclization

作者：Luo, Nian-hua; Sun, Xiang; Yan, Yun-yun; Nie, Shao-zhen; Yan, Ming^*

来源：Tetrahedron: Asymmetry , 2011, 22(14-15): 1536-1541.

DOI：10.1016/j.tetasy.2011.08.022

• BETA-KETO-ESTERS
• HIGHLY ENANTIOSELECTIVE SYNTHESIS
• N-BOC-ALDIMINES
• CONJUGATE ADDITION
• CINCHONA ALKALOIDS
• HETEROCYCLIC-ANALOGS
• MICHAEL-ALDOL
• AMINO ACIDS
• ACYL IMINES
• NITROCYCLOPROPANES

The organocatalytic asymmetric Mannich reaction of ethyl 4-chloro-3-oxobutanoate with N-Boc-imines has been studied and Cinchona alkaloids and chiral thiourea-tertiary amines were evaluated as catalysts. A pyrrolidine-based thiourea-tertiary amine was identified as the best catalyst for the transformation. The Mannich adducts readily underwent a one-pot intramolecular cyclization in the presence of triethylamine. A number of O-ethyl tetronic acid derivatives were obtained in good yields and enantioselectivities (up to 91% ee). The products could be further converted to the heteroatomic mimics of prostaglandins via reaction with primary amines.

• 出版日期2011-7-31
• 单位中山大学