Fluoroalkylated α,β‐Unsaturated Imines: Efficient and Versatile Substrates for the Synthesis of Fluorinated Vinylogous β‐Amino Esters and 3,4‐Dihydropyridin‐2‐ones

Abstract

Abstract A simple and efficient synthesis of vinylogous fluoroalkylated β‐amino mono‐ ( 4 ) and diester ( 9 ) derivatives by the regioselective 1,2‐addition of enolates derived from alkyl acetates or diethyl malonate to fluoroalkylated α,β‐unsaturated imines ( 1 ) is described. These fluorinated imines ( 1 ) were used as intermediates in the regioselective synthesis of fluorine‐containing trans ‐3,4‐dihydropyridin‐2‐ones ( 6 , 8a , 8b , 10 ) and 3,3‐spiro‐3,4‐dihydropyridin‐2‐ones ( 8c – h ) by conjugate (1,4‐) addition of enolates derived from α‐mono‐ and α,α‐disubstituted esters. Fluoroalkylated β‐amino esters ( 4 , 9 ) and 3,4‐dihydropyridin‐2‐ones ( 6 , 8 , 10 ) were also prepared by the olefination of enaminophosphonate 2 with BuLi, addition of aldehydes and subsequent addition of the enolates derived from esters 3 .