158706-34-4Relevant academic research and scientific papers
Simple preparation of cobaloxime dienyl complexes and their exo selective Diels-Alder cycloadducts. Progress toward transition metal-mediated Diels-Alder reactions which are catalytic in metal dienyl complex
Pickin, Kerry A.,Kindy, Jennifer M.,Day, Cynthia S.,Welker, Mark E.
, p. 120 - 133 (2007/10/03)
A new method for the synthesis of cobaloxime dienyl complexes (cobaloxime=pyridine(dimethylglyoxime)2Co) which involves a zinc-mediated hydrocobaltation of enynes is reported. Use of this dienyl complex synthesis method allows subsequent Diels-Alder reactions of these complexes to be accomplished without isolation of the dienyl complexes. A new silane-based cobaloxime-substituted cycloadduct demetallation protocol is then reported which provides Diels-Alder cycloadducts and cobalt complexes which have been recycled into the zinc-mediated dienyl complex synthesis.
Synthesis of cobalt-substituted 1,3-diene complexes with unusual structures and their exo-selective Diels-Alder reactions
Wright, Marcus W.,Smalley Jr., Terrence L.,Welker, Mark E.,Rheingold, Arnold L.
, p. 6777 - 6791 (2007/10/02)
The synthesis and characterization (including crystallographic data) of several substituted-pyridine (Rpyr) cobalt bis(dimethylglyoxime) 1,3-butadiene complexes (R = H, tBu, 3,5-diMe, and N,N-dimethylamino) and their Diels-Alder reactions with a variety of dienophiles are reported here. The cobalt-carbon bonds in the Diels-Alder cycloadducts can be cleaved so that cobalt complexes as well as functionalized organic cycloadducts are recovered. Through these cobalt-carbon bond cleavage reactions, cobalt-diene complexes can serve as synthons for a variety of 1,3-dienes such as 1,3-butadiene, 2-(trimethylsiloxy)- 1,3-butadiene, iodoprene, (E)-1-methoxy-3-(trimethylsiloxy)-1,3-butadiene (Danishefsky's diene), and 1,2-dichloro-1,3-butadiene. The preparation of several cobalt-substituted 1,2- and 1,3-pentadiene complexes and highly exo-selective Diels-Alder reactions of the 1,3-pentadiene complexes are then discussed followed by demetalation reactions of these more highly substituted cobalt cycloadducts. These demetalation reactions maintain the stereochemical integrity found in the metal cycloadducts and also lead to cobalt recovery.
