作者:Doyle J. Cassar、Hemin Roghzai、Didier Villemin、Peter N. Horton、Simon J. Coles、Christopher J. Richards
DOI:10.1021/acs.organomet.5b00282
日期:2015.6.22
of the new element of planar chirality was established by X-ray crystallography. These outcomes contrast with the opposite sense of diastereoselectivity observed for the corresponding R = i-Pr-substituted oxazoline, which results in the palladacycle (S,Rp)-COP-OAc (acetic acid solvent), these palladation reactions being under either kinetic (S,Sp) or thermodynamic (S,Rp) control. Following conversion
的Palladation(η 5 - (小号)-2-(4--R取代的)oxazolinylcyclopentadienyl)(η 4 -tetraphenylcyclobutadiene)钴(I)用Pd(OAc)2(R = Me中,CH 2 CY,CH 2我- Pr,CH 2 Ph)仅导致形成(S,S p)-Palladacycle,R = CH 2 Cy(乙酸溶剂),选择性高达13:1,有利于(S,S p)-Palladacycle其中R = CH 2 i -Pr(CH 2 Cl 2溶剂)。在后一种情况下,通过重结晶获得非对映异构体纯度,并通过X射线晶体学确定平面手性新元素的绝对构型。这些结果与相应的R = i -Pr取代的恶唑啉所观察到的非对映选择性相反,这导致了palladacycle(S,R p)-COP-OAc(乙酸溶剂),这些化反应在任一动力学下(S,S p)或热力学(S,R p)控制。转化为氯桥联(S,S