Oxidative addition of N-halosuccinimides to palladium(0): the discovery of neutral palladium(II) imidate complexes, which enhance Stille coupling of allylic and benzylic halides
作者:Catherine M. Crawforth、Suzanne Burling、Ian J.S. Fairlamb、Anant R. Kapdi、Richard J.K. Taylor、Adrian C. Whitwood
DOI:10.1016/j.tet.2005.06.080
日期:2005.10
mediate the Stille coupling of allylic and benzylichalides with alkenyl, aryl and allyl stannanes. In competition experiments between 4-nitrobromobenzene and benzyl bromide with a cis-stannylvinyl ester, (Ph3P)2Pd(N-Succ)Br preferentially cross-couples benzyl bromide, whereas with other commonly employed precatalysts 4-nitrobromobenzene undergoes preferential cross-coupling. Furthermore, preferential
Efficient and selective Stille cross-coupling of benzylic and allylic bromides using bromobis(triphenylphosphine)(N-succinimide)palladium(II)
作者:Catherine M. Crawforth、Ian J.S. Fairlamb、Richard J.K. Taylor
DOI:10.1016/j.tetlet.2003.11.014
日期:2004.1
[Pd(NCOC2H4CO)(PPh3)2Br] 1. Significantly, these reactions do not require the use of hexamethylphosphoramide (HMPA) as the solvent, or additional ligands, such as trifurylphosphine or triphenylarsine. Selectivity for benzyl bromide over bromobenzene is observed for precatalyst 1, against the precatalysts, bromobis(triphenylphosphine)(benzyl)palladium(II) and bis(triphenylphosphine)palladium(II) bromide.
使用预催化剂[Pd(NCOC 2 H 4 CO)(PPh 3)2 Br] 1可以使烯丙基和苄基溴与有机锡烷交联。重要的是,这些反应不需要使用六甲基磷酰胺(HMPA)作为溶剂,也不需要使用其他配体,例如三糠基膦或三苯基ar。对于预催化剂1,观察到苄基溴对溴苯的选择性相对于预催化剂溴双(三苯基膦)(苄基)钯(II)和双(三苯基膦)钯(II)。
Chiral Counteranion Strategy for Asymmetric Oxidative C(sp<sup>3</sup>)H/C(sp<sup>3</sup>)H Coupling: Enantioselective α-Allylation of Aldehydes with Terminal Alkenes
作者:Pu-Sheng Wang、Hua-Chen Lin、Yu-Jia Zhai、Zhi-Yong Han、Liu-Zhu Gong
DOI:10.1002/anie.201408199
日期:2014.11.3
The first enantioselective α‐allylation of aldehydes with terminalalkenes has been realized by combining asymmetriccounteranion catalysis and palladium‐catalyzed allylic CH activation. This method can tolerate a wide scope of α‐branched aromatic aldehydes and terminalalkenes, thus affording allylation products in high yields and with good to excellent levels of enantioselectivity. Importantly,
Palladium-catalyzed cross-coupling reaction of allyl carbonates with organostannanes
作者:Ana M. Castaño、Antonio M. Echavarren
DOI:10.1016/0040-4039(96)01406-2
日期:1996.9
Allylcarbonates are excellent substrates for the palladium(0)-catalyzed coupling reaction with stannanes under very mild conditions. The reaction proceeds via (η3-allyl)palladium complexes which undergo syn-anti equilibration with a rate similar to that of the transmetallation step.
The Cu-catalyzed synthesis of skipped 1,4-dienes from allylic acetates and vinyl-Grignard reagents is key to bidirectional modifications of acyclic terpene acetates. As a result, trisubstituted double bond containing subunits can be readily transferred into complex polyketides from inexpensive bulk terpenes.