10292-56-5Relevant academic research and scientific papers
Kinetic and modeling studies on the nickel-catalyzed Homo-Diels-Alder addition of 7-substituted norbornadienes
Gugelchuk,Doherty-Kirby
, p. 3490 - 3495 (1996)
Pseudo-first-order rate constants have been determined for several 7-substituted norbornadienes in their nickel-catalyzed homo-Diels-Aider cycloaddition with methyl vinyl ketone. The rate of reaction was slightly influenced by the nature of the substituent. Relative reactivities followed the order 7-Ph > H > 7-OTIPS. The observed activation parameters (ΔH? = 15-18 kcal/mol; ΔS? = -19 to -24 cal/mol K) were also affected by the 7-substituent and are in good agreement with those established for reductive elimination from related nickel phosphine complexes. With regard to regioselectivity, the more reactive norbornadiene was also the less selective. Force field modeling studies of possible organonickel intermediates suggest that the preferred exo selectivity arises from steric interactions between the dienophile substituent and the phosphine ligands. Good qualitative and quantitative agreement with observed exo stereoselectivity was found with three of the five model systems studied. Of these three models, reasonably good agreement with regioselectivity was found with only one of them.
Stereoselectivity in the Homo Diels-Alder Reaction
Lautens, Mark,Edwards, Louise G.
, p. 6813 - 6816 (2007/10/02)
Ni(COD)2/Ph3P or Ni(acac)2/Et3Al/Ph3P have been shown to be effective catalysts for the stereoselective homo Diels-Alder reaction between norbornadiene and electron deficient olefins.High and opposite stereoselectivity was observed for cyclic and acyclic enones.Vinyl sulfoxides gave predominantly one isomer, whereas vinyl sulfones were non-selective.
