Gold-Catalyzed Intramolecular Allylation of Silyl Alkynes Induced by Silane Alcoholysis
摘要:
The activation of alkynyl allyl silanes with a cationic gold catalyst in the presence of alcohols provides vinyl silanes that contain the allyl group at the beta-position and the alkoxysilyl group in cis-orientation. The bond reorganization process is most consistent with the involvement of a carbocationic intermediate, which undergoes a nucleophilic attack by an alcohol selectively at the silicon center. The cis-vinyl silyl ether products can be further elaborated by ring-closing and cross metathesis to form more substituted 1,4-dienyl silanes.
silyltriflates are valuable reagents in organosiliconchemistry. Triflate derivatives of polysilylacetylenes [(CF3SO3)RSiC-C]n. and polysilyldiacetylenes [(CF3SO3)RSiCCCC]n. are obtained by reaction of the corresponding allyl derivatives with trifluoromethane-sulfonic acid. The compounds show a high reactivity with nucleophiles. The reactions lead to new functional substituted polysilylacetylenes
高反应性的甲硅烷基三氟甲磺酸酯是有机硅化学中有价值的试剂。聚甲硅烷基乙炔的三氟甲磺酸衍生物[(CF 3 SO 3)RSiC-C] n。和聚硅烷基二乙炔[(CF 3 SO 3)RSiCCCC] n。通过使相应的烯丙基衍生物与三氟甲烷-磺酸反应获得。该化合物显示出与亲核试剂的高反应性。反应产生新的官能取代的聚甲硅烷基乙炔。该聚合物通过NMR光谱法(29 Si,13 C,1 H)表征。
Inter- and Intramolecular Carbonylative Alkyne–Alkyne Coupling Reaction Mediated by Cobalt Carbonyl Complex
Inter- and intramolecular carbonylative coupling reactions proceed between alkynes possessing diphenylallylsilyl group mediated by dicobalt carbonyl complex under argon atmosphere. This coupling reaction directly provides various mono- and bicyclic cyclopentadienones in high yields. (C) 2000 Elsevier Science Ltd. All rights reserved.
Direct synthesis of cyclopentadienones by cobalt carbonyl-mediated carbonylative alkyne-alkyne coupling reaction
作者:Takanori Shibata、Toshihiro Ohta、Kenso Soai
DOI:10.1016/s0040-4039(98)01175-7
日期:1998.8
Dicobalt carbonyl complex mediates an intermolecular carbonylative coupling reaction between alkynylsilanes, The reaction proceeds under atmospheric pressure of argon and directly provides free cyclopentadienones in high yields (up to 99%). (C) 1998 Elsevier Science Ltd. All rights reserved.