126182-20-5Relevant academic research and scientific papers
Pd-Catalyzed Heck-Type Reactions of Allenes for Stereoselective Syntheses of Substituted 1,3-Dienes
Vine, Logan E.,Schomaker, Jennifer M.
, (2021/11/16)
A highly stereoselective Pd-catalyzed Heck-type reaction of allenes in which the stereochemistry of both olefins is set simultaneously was developed. The ligand CyJohnPhos was crucial to achieving stereoselectivity, while minimizing isomerization of the starting material through hydropalladation. The stereodetermining factors were proposed to be A1,3 strain between the catalyst and allene substituent, which influences the σ-π-σ equilibrium of the coupled allene intermediate, as well as eclipsing interactions of R groups in the β-hydride elimination. Good functional group tolerance and stereoselectivities for formation of the Z,E isomer were demonstrated. The methodology was further expanded to include the regioselective formation of 2,4-dienoates and 2,4-dienamides with a variety of substitution patterns, albeit in reduced stereoselectivities favoring the E,E isomer. A plausible mechanism is proposed to account for the observed selectivities and substituent effects.
PALLADIUM-CATALYSED STEREOSELECTIVE HYDROVINYLATION OF DISUBSTITUTED ACETYLENES: PREPARATION OF FUNCTIONALIZED 1,2,4-TRISUBSTITUTED-1,3-DIENES
Arcadi, A.,Bernocchi, E.,Burini, A.,Cacchi, S.,Marinelli, F.,Pietroni, B.
, p. 3465 - 3468 (2007/10/02)
Vinyl halides react with disubstituted acetylenes in the presence of the palladium-formate reducing system to give stereoselective formation of functionalized 1,2,4-trisubstituted-1,3-dienes in good to high yield.With arylethynyl,dialkylcarbinols this rea
