Reaction of olefins and dienes with binuclear rhodium hydride complexes to generate bridging alkenyl, dienyl and diene units
作者:Michael D. Fryzuk、Warren E. Piers
DOI:10.1016/s0277-5387(00)86320-2
日期:1988.1
governed by the steric requirements of both the chelating phosphine ligand and the diene. In some cases, mononuclear methyl substituted allyl complexes are produced either as side products, or as the major products. The binuclear compounds may alternatively be synthesized via reaction between the chlorobridged dimers [R2P(CH2)nPR2Rh]2(μ-C1)2 (n = 2,3; R = Przi) and magnesium diene reagents; indeed this
式[R 2 P(CH 2)n PR 2 } Rh] 2(μ-H)2(1a:n = 2,R = Pr i ; 1b:ñ = 3,R = PR我)被发现与烯烃和二烯化学计量反应。对烯烃的反应性受辅助双膦配体的空间性质影响。化合物1a与多种简单的烯烃反应,生成式[(dippe)Rh] 2(μ-η )的双核桥联烯基-氢化物配合物2 -σ-RCCH(R)(μ-H),而1b结合了更大的空间体积的dipp配体,仅与乙烯反应。在这些复合物的μ链烯基配体显示出公知的“风挡刮水器” fluxionality,具有Δ ģ ‡12.2(2)千卡摩尔-1发现[(dippe)的Rh] 2(μ-η 2 -σ-HC CH 2)(μ-H),2A。这些反应的拟议机制包括用一当量的烯烃对二氢化物进行脱氢,然后使第二当量的烯烃与瞬态[(P 2)Rh] 2 d 9 - d 9 Rh(O)二聚体反应。二氢化物1a和1b还与1,