作者:Christopher A. Discolo、Eric E. Touney、Sergey V. Pronin
DOI:10.1021/jacs.9b10645
日期:2019.11.6
Asymmetric intramolecular hydrofunctionalization of tertiary allylic alcohols is described. This metal hydride-mediated catalytic radical-polar crossover reaction delivers corresponding epoxides in good to high enantioselectivity and constitutes the first example of asymmetric hydrogen atom transfer-initiated process. A series of modified cobalt salen complexes has proven optimal for achieving good
Process for preparing conjugated dienes using substituted rhenium
申请人:Eastman Chemical Company
公开号:US05929298A1
公开(公告)日:1999-07-27
This invention provides a process for preparing conjugated dienes using certain substituted rhenium compounds as catalysts. The substituted rhenium compounds have the formula R.sub.5 ReO.sub.3, wherein R.sub.5 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, aryl, aryl-C.sub.1 -C.sub.10 alkyl, cyclopentadienyl and cyclopentadienyl substituted with one to four C.sub.1 -C.sub.4 alkyl groups. The process of the invention thus provides a facile method for preparing conjugated dienes using the corresponding tertiary vinyl alcohol as starting material. Examples of such starting materials includes phytols, manool, 5-vinyl-5-nonanol, 1-vinyl4-tert-butylcyclohexanol, and 1-vinylcyclooctanol. The process can be carried out neat as well as in an inert solvent in the gas or solution phase.
Hydrovinylation of 1,3-Dienes: A New Protocol, an Asymmetric Variation, and a Potential Solution to the Exocyclic Side Chain Stereochemistry Problem
作者:Aibin Zhang、T. V. RajanBabu
DOI:10.1021/ja0561338
日期:2006.1.1
Cyclic and acyclic 1,3-dienes undergo efficient (substrate/catalyst = 72) heterodimerization with ethylene in the presence of a Ni catalyst prepared from [o-(PhCH2O)]C6H4PPh2, [(allyl)2NiBr]2, and Na+ BAr4- (Ar = 3,5-bis-trifluromethylphenyl), giving 1,2-addition products. Yields up to 99% can be realized for several 1-vinylcycloalkenes and 1-substituted 1,3-butadienes. Phospholanes with suitably placed hemilabile ligating groups and phosphoramidites derived from binaphthol are excellent ligands for an asymmetric variation of this reaction, the latter giving 99% yield and >95% ee's for selected substrates. An example of how an exocyclic chiral center can be used to install other stereo-centers in the ring (e. g., the carbon to which the side chain is attached) is also provided. These discoveries open an expeditious entry into several biologically relevant classes of compounds, especially those carrying tetrahydronaphthalene and related heterocyclic moieties.
FIAUD, J. C.;LEGROS, J. Y., J. ORGANOMET. CHEM., 370,(1989) N-3, C. 383-396
作者:FIAUD, J. C.、LEGROS, J. Y.
DOI:——
日期:——
FIAUD, JEAN-CLAUDE;LEGROS, JEAN-YVES, J. ORG. CHEM., 55,(1990) N6, C. 4840-4846