Ketene bis(trimethylsilyl) acetals. Cross-aldol type condensation reactions with aldehydes and schiff bases
作者:Jacques-Emile Dubois、Georges Axiotis
DOI:10.1016/s0040-4039(01)81183-7
日期:1984.1
Condensation of the title acetals with aldehydes and Schiff bases in the presence of titanium tetrachloride is reported for the first time. It leads to β-hydroxyacids and to β-lactams via a cross-aldol type reaction, with good yields.
Chiral tris(oxazoline)/Cu(ii) catalyzed coupling of terminal alkynes and nitronesElectronic supplementary information (ESI) available: experimental. See http://www.rsc.org/suppdata/cc/b3/b306653c/
Novel chiral iPr-tris(oxazoline)/Cu(ClO4)2 x 6H2O catalyzedcoupling of terminal acetylenes and nitrones to afford cis-disubstituted beta-lactams is described; the choice of base proves essential to both the diastereoselectivity and the enantioselectivity.
描述了新颖的手性iPr-三(恶唑啉)/ Cu(ClO4)2 x 6H2O催化的末端乙炔和硝酮的偶联,得到顺式二取代的β-内酰胺。碱的选择被证明对非对映选择性和对映选择性都是必不可少的。
Enantioselective synthesis of β-lactams via the IndaBox–Cu(II)-catalyzed Kinugasa reaction
The enantioselective Kinugasareaction of nitrones with terminal alkynes in the presence of 20 mol % of IndaBox–Cu(OTf)2 and di-sec-butylamine (1.5 equiv) produced β-lactams with the highest level of enantiomeric excesses among the catalytic enantioselective Kinugasareactions reported so far.
Optimized aqueous Kinugasa reactions for bioorthogonal chemistry applications
作者:Didier A. Bilodeau、Kaitlyn D. Margison、Noreen Ahmed、Miroslava Strmiskova、Allison R. Sherratt、John Paul Pezacki
DOI:10.1039/c9cc09473c
日期:——
surfactant micelles. We have investigated the factors that accelerate the aqueous CuANCR reaction and demonstrate enhanced modification of a model membrane-associated peptide. We discovered that lipids/surfactants and alkyne structure have a significant impact on the reaction rate, with biological lipids and electron-poor alkynes showing greater reactivity. These new findings have implications for the
enantioselective Kinugasa reactions between acyclic and, for the first time, cyclic nitrones and terminal alkynes are described herein. A catalytic amount of the readily available PINAP/CuX complexes, generated in situ, efficiently catalyzed the Kinugasa reactions, leading to a series of β-lactams with good enantioselectivities and moderate diastereoselectivities and yields. A broad range of nitrones and terminal
本文首次描述了无环与环状硝酮和末端炔烃之间的催化对映选择性 Kinugasa 反应。催化量的容易获得的 PINAP/CuX 复合物,原位生成,有效地催化了衣笠反应,产生了一系列具有良好对映选择性和中等非对映选择性和产率的 β-内酰胺。在反应条件下可以耐受广泛的硝酮和末端炔烃,包括很少报道的烷基取代炔烃。Further investigations proved that the PINAP/CuX catalytic system enabled the synthesis of monobactams on the gram scale (without loss of stereoselectivity and yield) and also both enantiomers by the appropriate choice of readily available atropisomeric