Rate Enhancement of the Pauson–Khand Reaction by Primary Amines

(Cycloheptyne)dicobalt Complexes in Organic Synthesis

“…Pauson-Khand reactions of (cycloheptyne)dicobalt complexes. tion in reasonable yields, predominantly under the Sugihara conditions; [44] tethers forming both five-and six-membered rings participate well. The cis isomers are formed predominantly.…”

Pauson–Khand Reaction of Allenic Hydrocarbons: Synthesis of 4‐Alkylidenecyclopentenones

“…Major improvements in the PKR came from finding new energetically activated procedures [15] or by using milder conditions with various promoters such as silica, [16] amines, [17] dimethylsulfoxide (DMSO), [18] sulfides [19] and molecular sieves. [20] Particularly, the use of tertiary amine N-oxides allowed the reaction to be carried out at room temperature.…”

Synergetic Effects of Oxidative and Coordinative Promotors to Increase the Yield of a Twofold Pauson−Khand Reaction

“…Especially helpful was the use of mild oxidation agents as promoters. [9,12] It is generally accepted that reagents such as dimethyl sulfoxide (DMSO) [11] or Nmethylmorpholine N-oxide (NMO) [9,10] remove one of the CO groups of the intermediate alkyneϪCo 2 (CO) 6 complex 1 by oxidizing it to carbon dioxide (Scheme 1). Scheme 1 Other species which were used to accelerate the reaction were donor ligands such as ethers, amines, or sulfides, [12Ϫ14] which are able to stabilize an empty site on the cobalt nucleus in 1 by a reversible complexation.…”