7-<i>e</i><i>ndo</i> Radical Cyclizations Catalyzed by Titanocene(III). Straightforward Synthesis of Terpenoids with Seven-Membered Carbocycles
作者:José Justicia、Juan L. Oller-López、Araceli G. Campaña、J. Enrique Oltra、Juan M. Cuerva、Elena Buñuel、Diego J. Cárdenas
DOI:10.1021/ja054316o
日期:2005.10.1
We describe a novelprocedure for the straightforward synthesis of seven-membered carbocycles via free-radical chemistry, based on titanocene(III)-catalyzed 7-endo-dig and 7-endo-trig cyclizations. This procedure has proved to be useful for the chemical preparation of terpenoids with different skeletons containing cycloheptane rings, including the first total syntheses of dauca-4(11),8-diene (2), barekoxide
Selective epoxidation of monoterpenes with methyltrioxorhenium and H2O2
作者:Aída L.P. de Villa、Dirk E. De Vos、Consuelo C. de Montes、Pierre A. Jacobs
DOI:10.1016/s0040-4039(98)01853-x
日期:1998.11
terpenes such as α-pinene with H2O2 with minimal rearrangement of the epoxide. Pyridine is also critical to suppress isomerisation of the olefin substrate (in case of nerol, geraniol). The reaction can be directed towards selective single or double epoxidation, or in one step towards the rearranged product (e.g. from linalool to the ring-closure product linalool oxide).
在吡啶作为助催化剂的存在下,CH 3 ReO 3以最小的环氧基重排催化H 2 O 2对萜烯(如α-pine烯)的环氧化。吡啶对于抑制烯烃底物的异构化也是至关重要的(如果是神经醇,香叶醇)。该反应可以针对选择性的单或双环氧化,或在一步中针对重排的产物(例如从芳樟醇到闭环产物芳樟醇氧化物)。
Catalytic Coupling of Carbon Dioxide with Terpene Scaffolds: Access to Challenging Bio-Based Organic Carbonates
作者:Giulia Fiorani、Moritz Stuck、Carmen Martín、Marta Martínez Belmonte、Eddy Martin、Eduardo C. Escudero-Adán、Arjan W. Kleij
DOI:10.1002/cssc.201600238
日期:2016.6.8
oxides and carbon dioxide into bio‐based cyclic organic carbonates catalyzed by Al(aminotriphenolate) complexes is reported. Both acyclic as well as cyclic terpene oxides were used as coupling partners, showing distinct reactivity/selectivity behavior. Whereas cyclic terpene oxides showed excellent chemoselectivity towards the organic carbonate product, acyclic substrates exhibited poorer selectivities
Ethyl Cyanoformate/Hydrogen Peroxide and Related Combination Systems, Novel Epoxidizing Systems of Olefins
作者:Yukio Masaki、Tsuyoshi Miura、Isao Mukai、Akichika Itoh、Hirohisa Oda
DOI:10.1246/cl.1991.1937
日期:1991.11
A combination system of ethyl cyanoformate and hydrogen peroxide was found to epoxidize olefins in a stereospecific manner at room temperature. Asymmetric epoxidation was observed with menthyl cyanoformate/hydrogen peroxide system.
Dirhodium(II)-Mediated Alkene Epoxidation with Iodine(III) Oxidants
作者:Ali Nasrallah、Gwendal Grelier、Maria Ivana Lapuh、Fernando J. Duran、Benjamin Darses、Philippe Dauban
DOI:10.1002/ejoc.201800306
日期:2018.11.15
combination of the dirhodium(II) complex Rh2(tpa)4 (tpa = triphenylacetate) with the iodine(III) oxidant PhI(OPiv)2 is shown to promote the epoxidation of alkenes in the presence of 2 equivalents of water. The reaction can be applied to diversely substituted alkenes and the corresponding epoxides are isolated with yields of up to 90 %. A possible mechanism involves the dirhodium(II) complex as a Lewis
Dirhodium (II) 络合物和碘 (III) 氧化剂已在合成氮烯化学中找到有用的应用。在这项研究中,二铑(II)配合物 Rh2(tpa)4(tpa = 三苯乙酸盐)与碘(III)氧化剂 PhI(OPiv)2 的组合被证明在 2 当量的水。该反应可应用于不同取代的烯烃,并以高达 90% 的产率分离相应的环氧化物。一种可能的机制涉及二铑 (II) 络合物作为路易斯酸物质,它可以调节碘 (III) 试剂的氧化特性。