General Preparation of 1‐Substituted (E)‐1,3‐Dienes under Mild Conditions

Abstract

We describe the stereoselective synthesis of highly functionalized 1-substituted (E)-1,3-dienes by reductive β-elimination of 2-chloroallyl acetates, derived from the indium-promoted allylation of aldehydes with 1,3-dichloropropene and subse-

Ohmic Heating and Ionic Liquids in Combination for the Indium‐Promoted Synthesis of 1‐Halo Alkenyl Compounds: Applications to Pd‐Catalysed Cross‐Coupling Reactions

“…Again, ohmic heating was much more efficient than classical heating, leading to an impressive decrease in the reaction time (from 12 to 1 h). The observed ( E ) configuration of the newly formed double bond, obtained through the β‐elimination process, can be explained according to a chelation‐control model 7…”

“…As a result of its low toxicity, environmental benefits and favourable effects on chemical transformations, indium metal has recently attracted considerable attention 4. It has been used extensively in carbon–carbon bond formation5 and reductive dehalogenation reactions,6 and recently our group7 and others8 have reported the use of indium in reductive elimination reactions.…”

Modern Synthetic Methods for the Stereoselective Construction of 1,3-Dienes

“…As a convenient alternative, Soengas and Rodríguez-Solla developed a methodology for stereoselective synthesis of ( E )-1,3-dienes which involves the reductive β-elimination of 2-chloroallyl acetates, prepared by indium-promoted allylation of aldehydes with commercially available and unexpensive 1,3-dichloropropene [ 175 ]. Thus, reductive β-elimination of 2-chloroallyl acetates promoted by either In/CuI or Mg/ZnCl 2 afforded ( E )-1-substituted-1,3-dienes in good yields with high control of the stereoselectivity ( Scheme 49 ).…”

Synthesis of Optically Active syn- and anti-Chlorohydrins through a Bienzymatic Reductive Cascade

“…Thus, Barbier allylation of a series of benzaldehydes 4a – g with 1,3-dichloroprop-1-ene ( 5 ) in the presence of indium powder (1.0 equiv) and sodium iodide (2.0 equiv) afforded the corresponding chlorohydrins 6a – g in good yields (68–88%) and moderate syn selectivities (79:21 to 81:19). 17 After oxidation with Dess–Martin periodinane (DMP), isomerization of the resulting β,γ-unsaturated chloroketones aided by silica gel exclusively afforded the more stable α,β-unsaturated chloroketones 1a – g in good yields (91–98%).…”

“…We envisioned the preparation of chloroenones by the indium-promoted allylation of aldehydes, followed by oxidation of the resulting racemic chlorohydrins and subsequent isomerization of the double bond to the more stable α,β-unsaturated position, as depicted in Scheme . Thus, Barbier allylation of a series of benzaldehydes 4a – g with 1,3-dichloroprop-1-ene ( 5 ) in the presence of indium powder (1.0 equiv) and sodium iodide (2.0 equiv) afforded the corresponding chlorohydrins 6a – g in good yields (68–88%) and moderate syn selectivities (79:21 to 81:19) . After oxidation with Dess–Martin periodinane (DMP), isomerization of the resulting β,γ-unsaturated chloroketones aided by silica gel exclusively afforded the more stable α,β-unsaturated chloroketones 1a – g in good yields (91–98%).…”