18409-21-7Relevant articles and documents
Selective Pinacol Coupling on Regeneratable Supported Acids in Sole Water
Sotto, Nicolas,Billamboz, Muriel,Chevrin-Villette, Carole,Len, Christophe
, p. 6375 - 6380 (2015/06/30)
Efficient pinacol coupling was developed in sole water, using a reusable heterogeneous supported acid source and zinc as cheap available metal source. This medium can be easily regenerated up to 10-fold without loss of activity. Moreover, supported acids enhance the selectivity of the pinacol coupling reaction compared with homogeneous acids.
Catalytic enantioselective allylation of dienals through the intermediacy of unsaturated π-allyl complexes
Zhang, Ping,Morken, James P.
supporting information; scheme or table, p. 12550 - 12551 (2010/01/30)
(Chemical Equation Presented) The nickel-catalyzed enantioselective addition of allylboronic acid pinacol ester [allylB(pin)] to >,β,γ,δ-unsaturated aldehydes is described. This reaction results in a remarkable inversion of substrate olefin geometry, providing the Z,E-configured reaction product in good enantioselectivity and olefin stereoselectivity. The reaction appears to proceed by conversion of the dienal to an unsaturated B-allyl complex followed by reductive elimination via transition state II. Enantioselectivities range from 73-94% ee for a range of δ-substituted dienals when chiral ligand L3 is employed.
Aggregation behavior of tetraenoic fatty acids in aqueous solution
Wang, Yonghui,Ma, Jianguo,Cheon, Hwan-Sung,Kishi, Yoshito
, p. 1333 - 1336 (2008/04/05)
(Chemical Equation Presented) Why so blue? Unique blue-shifted UV absorptions were used to follow the aggregation of C24 tetraene fatty acids in aqueous solution. Aggregation takes place through three distinct states (i.e. K→T1→T2; see picture). It is suggested that all of these aggregates are lamellar-type in a local sense but differ in the packing mode of the fatty acid backbone.
Carbenoid pathways in copper-catalyzed intramolecular cyclopropanations of phenyliodonium ylides
Mueller, Paul,Bolea, Christelle
, p. 1093 - 1111 (2007/10/03)
The enantioselectivity of the copper-catalyzed intramolecular cyclopropanation of allyl diazomalonates and the corresponding phenyliodonium ylides was investigated with a series of chiral, non-racemic ligands. The reaction of 6b in the presence of the bis[dihydrooxazole] ligand Xa in refluxing 1,2-dichloroethane proceeded to 8b with an enantiomer excess (ee) of up to 72% under optimized conditions. In contrast, 8b resulting from reaction of ylide 7b with the same ligand, but in CH2Cl2 at 0°, had an ee of only 30%. With other ligands, diazomalonate 6b reacted with a lower enantioselectivity than ylide 7b, however. The intramolecular cyclopropanation of the acetoacetate-derived phenyliodonium ylide 15b afforded 16b with 68% ee with ligand Xa, but the corresponding diazo compound was unreactive when exposed to chiral copper catalysts. The observation of asymmetric induction in the Cu-catalyzed reactions of the ylides 7 and 15 is consistent with a carbenoid mechanism however, the discrepancy of the enantioselectivities observed between diazomalonate 6b and ylide 7b suggests a competing unselective pathway for cyclopropanation outside of the coordination sphere of copper.
COMPOUNDS WITH A HERBAL ODOR III. CIS-ALKENES WITH AN OXYGEN FUNCTION AT THE β POSITION AND THEIR SYNTHESIS BY HYDROGENATION OF DIENE PRECURSORS AT CHROMIUM HEXACARBONYL
Vasil'ev, A. A.,Cherkaev, G. V.
, p. 834 - 840 (2007/10/02)
During the hydrogenation of dienes with oxygen functions at the α position in the presence of chromium hexacarbonyl 1,4-addition of hydrogen to the diene system occurs, and this leads to the corresponding cis-monoene derivatives.In the case of dienes with hydroxyl, alkoxyl, acetal, and ester groups the product yield approaches quantitative; the hydrogenation of similar oxo and acyloxy derivatives is less satisfactory.Many representatives of the synthesized compounds, in which the cis-disubstituted double bond is separated from the oxygen-containing functional group by two carbon atoms, have a herbal odor.
Total Synthesis of Frustulosin and Aurocitrin
Ronald, Robert C.,Lansinger, Janet M.,Lillie, Thomas S.,Wheeler, Carl J.
, p. 2541 - 2549 (2007/10/02)
The regioselective total syntheses of the novel fungal antibiotics frustulosin (1) and aurocitrin (2) were accomplished from 3,6-dihydroxy-2-iodobenzaldehyde (10) which was prepared by a regiodirected metalation of 2,5-dimethylbenzyl vinyl ether to establish the 1,2,3,4-tetrasubstitution pattern of these compounds.The unsaturated side chains of these hydroquinone antibiotics were attached by using the iodo aldehyde functionalities.The structures of these antibiotics are confirmed by synthesis.
Structural Dynamics of Pentadienyl Metal-Compounds Bearing a Terminal Alkyl Substituent: Both 'Stereoselective' and 'Stereodefensive' Synthesis of a Natural Perfume
Bosshardt, Herbert,Schlosser, Manfred
, p. 2393 - 2403 (2007/10/02)
The (2Z,4E)-, (2E,4Z)- and (2E,4E)-isomers of 2,4-decandien-1-ol (5) have been obtained with high and predictable stereochemical homogeneity starting from both (Z)- and (E)-1,4-decadiene.These hydrocarbons were hydroxylated in a reaction sequence consisting of metallation (by means of s-butyllithium or butyllithium/potassium-t-butoxide, giving rise to organometallic intermediates of specific conformations), dimethoxyborylation and oxidation.The different decadienols as well as (2E,4Z)-2,4-undecadien-1-ol were converted into the isovalerates, the ester derived from (2E,4Z)-2,4-decadien-1-ol being a natural flavor component.
