sequential treatment of an acetylide with a Fischercarbenecomplex and an alkene/diene yields alkynylcyclopropanes with a wide substitution range. The intramolecular process provides 1‐alkynylbicyclo[3.1.0]cyclohexanes by starting from 1,6‐enynes. A non‐heteroatom‐stabilized metal alkynylcarbene is responsible for the selectivetransfer of the propargylene unit.
Enantioselective Multicomponent Synthesis of Fused 6-5 Bicyclic 2-Butenolides by a Cascade Heterobicyclisation Process
作者:Marcos G. Suero、Raquel De la Campa、Laura Torre-Fernández、Santiago García-Granda、Josefa Flórez
DOI:10.1002/chem.201102288
日期:2012.6.4
heterobicyclisation products is the result of the regioselective integration of the Grignardreagent as a propargyl fragment followed by a cascade CO/alkyne/CO insertion, ketene trapping and elimination sequence. By using lithium enolates of chiral N‐acetyl‐2‐oxazolidinones and the corresponding propargylic organocerium reagents, both enantiomers of these bicyclic heterocycles were efficiently prepared with
Carbon-carbon bond formation via carbonyl-carbene complexes
作者:K. H. Dotz
DOI:10.1351/pac198355111689
日期:1983.1.1
demonstrated upon their reactions with alkynes. Both the electrophilicity of the carbene car— hon atom and the facile substitution of carbon monoxide are used for selective carbon carbon bond formation. Nucleophilic alkynes (ynamines) add to the carbene carbon atom and then undergo insertion into the metal carbene bond. Chromium(O) is effective as a template in the annulation of carbene ligands bearing aromatic
Physical Organic Chemistry of Transition Metal Carbene Complexes. 27. Substituent Effects on the Nucleophilic Substitution of [Aryl(thiomethyl)carbene]pentacarbonylchromium(0) Complexes by Amines in Aqueous Acetonitrile
作者:Claude F. Bernasconi、Santanu Bhattacharya
DOI:10.1021/om020955l
日期:2003.3.1
A kineticstudy of the reactions of (CO)5CrC(SMe)C6H4Z (Z = 4-CF3, 4-Cl, 4-F, 4-Me, 4-MeO, and 4-Me2N) with n-butylamine, 2-chloroethylamine, piperidine, and 1-(2-hydroxyethyl)piperazine in 50% MeCN−50% water (v/v) at 25 °C is reported. In all cases the nucleophilic attachment of the amine to the carbene complex is rate limiting, which contrasts with the previously reported aminolysis of the methoxy
(CO)5 Cr C(SMe)C 6 H 4 Z(Z = 4-CF 3,4 -Cl,4-F,4-Me,4-MeO和4-Me 2的反应动力学研究N)在25°C下于50%MeCN-50%水(v / v)中的正丁胺,2-氯乙胺,哌啶和1-(2-羟乙基)哌嗪进行了报道。在所有情况下,胺与卡宾配合物的亲核连接均受速率限制,这与先前报道的甲氧基类似物((CO)5 Cr C(OMe)C 6 H 4Z),在大多数情况下,离开小组的离开是限速的。取代基对亲核连接步骤的影响(平均ρ= 0.55)比甲氧基类似物(ρ= 2.03)弱得多。结果表明,(CO)5 Cr C(SMe)C 6 H 4 Z的小ρ值是“正常”的,反映了在过渡态时取代基对部分正电荷和部分负电荷的作用几乎抵消。这些发现提供了证据:(CO)5 Cr C(OMe)C 6 H 4 Z的高ρ值是“异常的”,并且是甲氧基对反应物卡宾络合物的强烈π供体作用的结果。
Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 6. Synthesis of platinum–chromium and –tungsten compounds. X-Ray crystal structure of [(Me<sub>3</sub>P)(OC)<sub>4</sub>W{µ-C(OMe)C<sub>6</sub>H<sub>4</sub>Me-4}Pt(PMe<sub>3</sub>)<sub>2</sub>]
作者:Judith A. K. Howard、Kevin A. Mead、John R. Moss、Rafael Navarro、F. Gordon A. Stone、Peter Woodward
DOI:10.1039/dt9810000743
日期:——
PR3= PMe3 or PMe2Ph), characterised by 31P and 1H n.m.r. spectroscopy. The compounds [(OC)5[graphic omitted](PMe2Ph)2], [(OC)5[graphic omitted](PMe2Ph)2], and [(OC)5[graphic omitted](PMe3)2] were similarly obtained from [WC(OMe)Me}(CO)5], [Cr([graphic omitted]H2)(CO)5], and [W(CPh2)(CO)5], respectively. Although [PtW(µ-CPh2)(CO)5(PMe3)2] is a relatively unstable complex, reaction with trimethylphosphine