IBX as a catalyst for dehydration of hydroperoxides: green entry to α,β-unsaturated ketones <i>via</i> oxygenative allylic transposition
作者:Tetsuya Kuga、Yusuke Sasano、Yoshiharu Iwabuchi
DOI:10.1039/c7cc08957k
日期:——
A catalytic transformation of allylic hydroperoxides into α,β-unsaturated carbonyl compounds using IBX as a dehydration catalyst is described. The combination of a singlet oxygen ene reaction and the IBX-catalyzed dehydration provides α,β-unsaturated carbonyl compounds from alkenes via oxygenativeallylictransposition with H2O as the only byproduct.
“Canopy Catalysts” for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework
作者:Julius Hillenbrand、Markus Leutzsch、Ektoras Yiannakas、Christopher P. Gordon、Christian Wille、Nils Nöthling、Christophe Copéret、Alois Fürstner
DOI:10.1021/jacs.0c04742
日期:2020.6.24
certain stability toward water, which marks a big leap forward in metal alkylidyne chemistry in general. At the same time, they tolerate many donor sites, including basic nitrogen and numerous heterocycles. This aspect is substantiated by applications to polyfunctional (natural) products. A combined spectroscopic, crystallographic, and computational study provides insights into structure and electronic
groups have the advantage that they are more stable within the coordination sphere of a high‐valent molybdenum center than tert‐alkoxides, which commonly served as ancillary ligands in previous generations of alkyne metathesis catalysts. From a practical point of view it is important to note that complexes of the general type [(Ar3SiO)3MoX] (X = N, CR; R = aryl, alkyl, Ar = aryl) can be rendered air‐stable
具有三芳基硅烷醇酸酯配体的钼的氮化物和亚烷基络合物是各种炔烃复分解反应的极好(预)催化剂,因为它们结合了高活性和对极性和/或敏感官能团的出色耐受性。结构和反应性数据表明,这种有希望的应用前景是由于高价钼中心的特征与所选Ar 3 SiO基团的电子和空间特征之间的良好匹配而产生的。这种相互作用确保了中心原子上路易斯酸度的均衡水平,这对于高活性至关重要。此外,笨重的硅烷醇化物虽然不利于有效的亚烷基单元的双分子分解,但不会阻碍底物的结合。另外,Ar 3SiO基的优势在于,它们在高价钼中心的配位范围内比叔醇盐更稳定,后者在上一代炔烃复分解催化剂中通常用作辅助配体。从实际的角度来看是要注意的一般类型[(AR的该配合物是重要的3的SiO)3 MoX](X = N,CR; R =芳基,烷基中,Ar =芳基)可以呈现空气在1,10-菲咯啉,2,2'-联吡啶或其衍生物的帮助下稳定。尽管所得的加合物本身具有催
Process for preparing optically active cyclopentenones
申请人:Sumitomo Chemical Company, Limited
公开号:US05191109A1
公开(公告)日:1993-03-02
An improved process for preparing an optically active 4-hydroxycyclopentenone of the formula: ##STR1## wherein R is a lower alkyl, the symbol means double bond or triple bond, and the * marked carbon is an asymmetric carbon, and the corresponding racemic 4-hydroxycyclopentenone, which are useful as an intermediate for preparing medicinal or agricultural products, particularly pharmaceutically active prostaglandins, and intermediates for preparing the optically active and/or racemic 4-hydroxycyclopentenone.