A General and Robust Method for the Preparation of (E)- and (Z)-Stereodefined Fully Substituted Enol Tosylates: Promising Cross-Coupling Partners

作者：Ashida Yuichiro; Sato Yuka; Honda Atsushi; Nakatsuji Hidefumi; Tanabe Yoo

来源：Synthesis (Germany), 2016, 48(23): 4072-4080.

DOI：10.1055/s-0035-1562482

• stereocomplementary
• stereodefined olefin
• enol tosylate
• tosyl chloride
• TMEDA
• diamine
• NMR monitoring

A robust method for preparing (E)- and (Z)-stereodefined fully substituted enol tosylates is described. alpha-Substituted beta-keto esters undergo (E)-selective enol tosylations using TsCl-Me2N(CH2)(6)NMe2 as the reagent (method A, 13 examples; 63-96%) and (Z)-selective enol tosylations using TsCl-TMEDA-LiCl as the reagent (method B, 13 examples; 62-99%). A plausible mechanism for the (E)- and (Z)-enol tosylation selectivity is proposed. A H-1 NMR monitoring experiment revealed that TsCl coupled with TMEDA formed a simple N-sulfonylammonium intermediate.

• 出版日期2016-12