Sodium Dithionite Initiated Addition‐lactonization of 2‐Acyl‐ amino‐4‐pentenoic Acids with Fluoroalkyl Iodides to Synthesize 4‐Fluoroalkyl‐2‐acylamino‐4‐butyrolactones

Abstract

4-Fluoroalkyl-2-acylamino-4-butyrolactones were afforded in moderate yields by the sodium dithionite initiated one-pot addition-lactonization reaction of polyfluoroalkyl iodides with 2-acylamino-4-pentenoic acids.

Polyfluorinated Ethanes as Versatile Fluorinated C2-Building Blocks for Organic Synthesis

“…Thus, a number of polyfluoroalkyl-γ-lactones 44 was synthesized from PFE and 4-pentenoic acids 43 in good yields (Scheme , Table ). In the case of α-amino pentenoic acid amides 43b , the reaction with ClCF 2 CF 2 I led to racemic lactones 44b and 44c (yields were not given) . In the case of conjugated E -isomer of dienoic acid 68 , having unfavorable configuration for the cyclization, the reaction with ICF 2 CF 2 Cl gave halide-free 1,4-adduct 69 with the E -configuration instead of the corresponding γ-lacton (Scheme ) …”

“…In the case of α-amino pentenoic acid amides 43b, the reaction with ClCF 2 CF 2 I led to racemic lactones 44b and 44c (yields were not given). 125 In the case of conjugated E-isomer of dienoic acid 68, having unfavorable configuration for the cyclization, the reaction with ICF 2 CF 2 Cl gave halide-free 1,4-adduct 69 with the E-configuration instead of the corresponding γ-lacton (Scheme 48). 126 Similarly, 4-pentenamides 70a gave γ-butyrolactones 44d, 44e in good yields by the reaction with ICF 2 CF 2 Cl.…”