The Isolation of [Pd{OC(O)H}(H)(NHC)(PR3)] (NHC = N-Heterocyclic Carbene) and Its Role in Alkene and Alkyne Reductions Using Formic Acid
摘要:
The [Pd(SIPr)(PCy3)] complex efficiently promotes a tandem process involving dehydrogenation of formic acid and hydrogenation of C-C multiple bonds using H-2 formed in situ. The isolation of a key catalytic hydridoformatopalladium species, [Pd{OC(O)H}(H)(IPr)(PCy3)], is reported. The complex plays a key role in the Pd(0)-mediated formation of hydrogen from formic acid. Mechanistic and computational studies delineate the operational role of the palladium complex in this efficient tandem sequence.
提出了阳离子Au I /手性磷酰胺配合物催化的1,6-烯炔的高度对映选择性氧化环丙烷化反应。该新方法可方便地获得具有三个高对映选择性(最高er 98:2)的稠密官能化双环[3.1.0]己烷,该己烷带有三个连续的季和叔立体异构中心。对照实验表明,反应中β-金乙烯基氧基喹啉鎓中间体的喹啉部分在过渡状态下通过过渡辅助作用在促进良好的对映选择性方面起着重要作用。
The Isolation of [Pd{OC(O)H}(H)(NHC)(PR<sub>3</sub>)] (NHC = N-Heterocyclic Carbene) and Its Role in Alkene and Alkyne Reductions Using Formic Acid
作者:Julie Broggi、Václav Jurčík、Olivier Songis、Albert Poater、Luigi Cavallo、Alexandra M. Z. Slawin、Catherine S. J. Cazin
DOI:10.1021/ja311087c
日期:2013.3.27
The [Pd(SIPr)(PCy3)] complex efficiently promotes a tandem process involving dehydrogenation of formic acid and hydrogenation of C-C multiple bonds using H-2 formed in situ. The isolation of a key catalytic hydridoformatopalladium species, [PdOC(O)H}(H)(IPr)(PCy3)], is reported. The complex plays a key role in the Pd(0)-mediated formation of hydrogen from formic acid. Mechanistic and computational studies delineate the operational role of the palladium complex in this efficient tandem sequence.
Gold(I)-Catalyzed Highly Diastereo- and Enantioselective Alkyne Oxidation/Cyclopropanation of 1,6-Enynes
A highlyenantioselective oxidative cyclopropanation of 1,6‐enynes catalyzed by cationic AuI/chiral phophoramidite complexes is presented. The new method provides convenient access to densely functionalized bicyclo[3.1.0]hexanes bearing three contiguous quaternary and tertiary stereogeniccenters with high enantioselectivity (up to e.r. 98:2). Control experiments suggest that the quinoline moiety of
提出了阳离子Au I /手性磷酰胺配合物催化的1,6-烯炔的高度对映选择性氧化环丙烷化反应。该新方法可方便地获得具有三个高对映选择性(最高er 98:2)的稠密官能化双环[3.1.0]己烷,该己烷带有三个连续的季和叔立体异构中心。对照实验表明,反应中β-金乙烯基氧基喹啉鎓中间体的喹啉部分在过渡状态下通过过渡辅助作用在促进良好的对映选择性方面起着重要作用。