Cyclisation of acetylenic carboxylic acids and acetylenic alcohols to oxygen-containing heterocycles using cationic rhodium(I) complexes
作者:Sarah Elgafi、Leslie D Field*、Barbara A Messerle*
DOI:10.1016/s0022-328x(00)00233-3
日期:2000.8
[mim=N-methylimidazol-2-yl, mBnzim=N-methylbenzimidazol-2-yl] are catalysts for the cyclisation of alkynoic acids to lactones. The unsaturated acids, 4-pentynoic acid, 4-hexynoic acid and 5-hexynoic acid were cyclised to γ-methylene-γ-butyrolactone, E-5-ethylidenetetrahydro-2-furanone and 6-methylidenetetrahydo-2-pyrone, respectively. Cyclisation of 4-hexynoic acid proceeds stereoselectively with exclusive formation
Silver-zeolite catalysed solvent free synthesis of (spiro)ketals
作者:Sophie Borghèse、Pauline Drouhin、Valérie Bénéteau、Benoit Louis、Patrick Pale
DOI:10.1039/c3gc40422f
日期:——
were able to catalyse, without solvents and at low silver loading, the formation of (spiro)ketals from alkyn(edi)ols. Such Ag-zeolite catalysts could be recycled without any activity loss. This study constitutes the first (spiro)ketalization mediated by silver heterogeneous catalysts, but also a truly ‘green’ (spiro)ketalization.
A Metal–Organic Framework with Cooperative Phosphines That Permit Post‐Synthetic Installation of Open Metal Sites
作者:Samuel G. Dunning、Gianne Nandra、Adam D. Conn、Wenrui Chai、R. Eric Sikma、Ji Sun Lee、Pranaw Kunal、Joseph E. Reynolds、Jong‐San Chang、Alexander Steiner、Graeme Henkelman、Simon M. Humphrey
DOI:10.1002/anie.201802402
日期:2018.7.20
PCM‐101 is a phosphine coordination material comprised of tris(p‐carboxylato)triphenylphosphine and secondary pillaring groups coordinated to [M3(OH)]5+ nodes (M=Co, Ni). PCM‐101 has a unique topology in which R3P: sites are arranged directly trans to one another, with a P⋅⋅⋅P separation distance dictated by the pillars. Post‐synthetic coordination of soft metals to the P: sites proceeds at room temperature
The cyclization of 3- or 4-pentyn-1-ol is catalysed by PdCl2 or trans-[PdCl2L2] (L = R-camphorimine; R = Ph; Pr-i; NMe2) complexes at room temperature affording heterocyclic compounds, respectively, 2-methyl-2-pent-3-ynyloxy-tetrahydrofuran or 2-methyl-2-pent-4-ynyloxy-tetrahydrofuran which subsequently add water to give selectively 5-(2-methyl-tetrahydrofuran-2-yloxy)-pentan-2-one from both starting materials. By hydrolysis 5-(2-methyl-tetrahydrofuran-2-yloxy)-pentan-2-one undergoes ring cleavage to form 5-hydroxy-2-pentanone. The catalytic activity and selectivity of complexes trans-[PdCl2L2] (L = R-camphorimine) depend on the characteristics of the R group (NMe2 > Pr-i > Ph). The catalytic activity of PdCl2 is comparable to that of trans-[PdCl2L2] (L = Ph-camphorimine) which is the less efficient catalyst. (c) 2006 Elsevier B.V. All rights reserved.