A general palladium-catalyzedsynthesis of linear esters directly from sec- and tert-alcohols is described. Compared to the classic Koch–Haaf reaction, which leads to branched products, this new transformation gives the corresponding linear esters in high yields and selectivity. Key for this protocol is the use of an advanced palladium catalyst system with L2 (pytbpx) as the ligand. A variety of aliphatic
直接从直链酯的一般钯催化合成的仲-和叔-醇进行说明。与导致分支产物的经典科赫-哈夫反应相比,这种新的转化以高收率和选择性提供了相应的线性酯。该协议的关键是使用具有L2(py t bpx)作为配体的高级钯催化剂体系。可以直接使用多种脂族和苄醇,基准反应的催化剂效率非常出色(周转数高达89 000)。
Rhodium-Catalyzed Heck-Type Coupling of Boronic Acids with Activated Alkenes in an Aqueous Emulsion
作者:Mark Lautens、John Mancuso、Harpreet Grover
DOI:10.1055/s-2004-829161
日期:——
Intermolecular couplings between arylboronic acids and activated alkenes catalyzed by a water-soluble tert-butyl amphosrhodium complex were found to progress at room temperature and generated Heck-type products with high yields and excellent selectivity. Substitution on the alkene component encouraged the formation of products arising from a conjugate addition-protonation process. In the case of Heck
Substituent effects in the mass spectra of some γ- and β-substituted methyl butyrates
作者:Ian Howe、Dudley H. Williams、David G. I. Kingston、Harvey P. Tannenbaum
DOI:10.1039/j29690000439
日期:——
Results are presented (relative ion abundances, I.P. and A.P. measurements) to illustrate substituent effects in the massspectra of some γ- and β-substituted methyl butyrates. It is argued that (i)‘sub-decomposition energy’ ions and (ii) competition in the source with fast fragmentation processes are important factors influencing parent/daughter ion ratios, which are then rationalised in terms of the