Synthesis of Fused Arylboronic Esters via Cobalt(0)-Mediated Cycloaddition of Alkynylboronates with α,ω-Diynes
摘要:
Co-2(CO)(6)-complexed alkynyl pinacolborane derivatives are readily transformed with functional group tolerance into fused arylboronates via the [2 + 2 + 2]cycloaddition to alpha,omega-diynes.
mechanism. Stoichiometric NMR studies as well as DFT calculations revealed that heterolytic coupling occurs between the siladiyne and alkyne followed by an internal [4+2] cycloaddition for CpCo(I)-catalyzed reactions, whereas Cp*Ru(II)Cl-catalyzed reactions proceeded via homolytic coupling of siladiynes to afford a ruthenacyclopentatriene followed by insertion of the alkynes. Minimum energy crossing point
Twofold Pauson–Khand reaction of acyclic and cyclic diynes with ethylene
作者:Bernhard J Rausch、Rolf Gleiter
DOI:10.1016/s0040-4039(01)00004-1
日期:2001.2
The twofold DMSO promoted Pauson–Khand reaction of acyclic heptadiynes 1–3, acyclic functionalized nonadiynediol derivatives 7–9 and cyclic diynes 13–15 with ethylene is reported.