Source:http://linkedlifedata.com/resource/pubmed/id/18373345
| Subject | Predicate | Object | Context |
|---|---|---|---|
| pubmed-article:18373345 | rdf:type | pubmed:Citation | lld:pubmed |
| pubmed-article:18373345 | lifeskim:mentions | umls-concept:C0001992 | lld:lifeskim |
| pubmed-article:18373345 | lifeskim:mentions | umls-concept:C0009968 | lld:lifeskim |
| pubmed-article:18373345 | lifeskim:mentions | umls-concept:C1704241 | lld:lifeskim |
| pubmed-article:18373345 | lifeskim:mentions | umls-concept:C2603343 | lld:lifeskim |
| pubmed-article:18373345 | lifeskim:mentions | umls-concept:C0441712 | lld:lifeskim |
| pubmed-article:18373345 | pubmed:issue | 16 | lld:pubmed |
| pubmed-article:18373345 | pubmed:dateCreated | 2008-4-18 | lld:pubmed |
| pubmed-article:18373345 | pubmed:abstractText | The detailed mechanism for the diboration of aldehydes catalyzed by (NHC)Cu(boryl) complexes (NHC = N-heterocyclic carbene) was studied with the aid of DFT by calculating the relevant intermediates and transition states. The results show that the catalyzed diboration occurs through aldehyde insertion into Cu-B to give a Cu-O-C(boryl) species followed by sigma-bond metathesis with a diboron reagent. It is the "electron-richness", that is, the nucleophilicity of the Cu-boryl bond, which gives rise to a small insertion barrier and determines the direction of insertion. The results of our calculations also explain the formation of the product, observed experimentally, from the stoichiometric reaction of (IPr)Cu-Bpin (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with mesitylaldehyde. In the absence of a diboron reagent, the insertion intermediate having a Cu-O-C(boryl) linkage isomerizes to the thermodynamically preferred Cu-C-O(boryl) isomer via a boryl migration to the metal-bonded oxygen through an S(E)2-like transition state. We have also studied the catalyzed diboration of 2-pyridinecarboxaldehyde, which gives the unexpected reductive coupling product 1,2-di-2-pyridyl-1,2-bis(pinacolboroxy)ethane. The insertion intermediate, which contains a coordinated pyridyl group, isomerizes easily to a 1,2-dihydropyridine form, preventing its metathesis with a diboron reagent to give the expected diboration product as observed for other aldehyde substrates. | lld:pubmed |
| pubmed-article:18373345 | pubmed:language | eng | lld:pubmed |
| pubmed-article:18373345 | pubmed:journal | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:18373345 | pubmed:status | PubMed-not-MEDLINE | lld:pubmed |
| pubmed-article:18373345 | pubmed:month | Apr | lld:pubmed |
| pubmed-article:18373345 | pubmed:issn | 1520-5126 | lld:pubmed |
| pubmed-article:18373345 | pubmed:author | pubmed-author:LinZhenyangZ | lld:pubmed |
| pubmed-article:18373345 | pubmed:author | pubmed-author:ZhaoHaitaoH | lld:pubmed |
| pubmed-article:18373345 | pubmed:author | pubmed-author:MarderTodd... | lld:pubmed |
| pubmed-article:18373345 | pubmed:author | pubmed-author:DangLiL | lld:pubmed |
| pubmed-article:18373345 | pubmed:issnType | Electronic | lld:pubmed |
| pubmed-article:18373345 | pubmed:day | 23 | lld:pubmed |
| pubmed-article:18373345 | pubmed:volume | 130 | lld:pubmed |
| pubmed-article:18373345 | pubmed:owner | NLM | lld:pubmed |
| pubmed-article:18373345 | pubmed:authorsComplete | Y | lld:pubmed |
| pubmed-article:18373345 | pubmed:pagination | 5586-94 | lld:pubmed |
| pubmed-article:18373345 | pubmed:year | 2008 | lld:pubmed |
| pubmed-article:18373345 | pubmed:articleTitle | DFT studies on the mechanism of the diboration of aldehydes catalyzed by copper(I) boryl complexes. | lld:pubmed |
| pubmed-article:18373345 | pubmed:affiliation | Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. | lld:pubmed |
| pubmed-article:18373345 | pubmed:publicationType | Journal Article | lld:pubmed |