Catalytic Enantioselective Addition of an Allyl Group to Ketones Containing a Tri-, a Di-, or a Monohalomethyl Moiety. Stereochemical Control Based on Distinctive Electronic and Steric Attributes of C–Cl, C–Br, and C–F Bonds
作者:Diana C. Fager、KyungA Lee、Amir H. Hoveyda
DOI:10.1021/jacs.9b08443
日期:2019.10.9
products enantioselectively but also in some cases there are hardly any instances of a catalytic enantioselectiveaddition of a carbon-based nucleophile (e.g., one enzyme-catalyzed aldol addition involving trichloromethyl ketones, and none with dichloromethyl, tribromomethyl, or dibromomethyl ketones). The approach is scalable and offers an expeditious route to the enantioselectivesynthesis of versatile
Transition-Metal-Free Transformation of Aryl Bromides into Aromatic Esters and Amides via Aryl Trichloromethyl Ketones
作者:Souya Dohi、Katsuhiko Moriyama、Hideo Togo
DOI:10.1002/ejoc.201301170
日期:2013.12
Arylbromides have been treated with Mg and then chloral, followed by tBuOCl or tBuOCl with I2 as an additive, and subsequently alcohols or amines to form the corresponding aromaticesters and aromaticamidesviaaryltrichloromethylketones as intermediates.
Chemoselective Reduction of Trichloromethyl Compounds to <i>gem</i>-Dichloromethyl Groups Following Appel’s Reaction Protocol
作者:Moises A. Romero-Reyes、Ivann Zaragoza-Galicia、Horacio F. Olivo、Moises Romero-Ortega
DOI:10.1021/acs.joc.6b02044
日期:2016.10.7
trichloroacetyl compounds following the modification of Appel’s reaction protocol, using triphenylphosphine and methanol, afforded the corresponding dichloroacetyl compounds, with the exception of trichloroacetylmorpholine, in yields of 80–98% under very mild experimental conditions. Likewise, when trichloromethyl heterocyclic compoundscontain another reactive functional group, the reaction is highly chemoselective
can be prepared by the catalytic enantioselective cross-aldol reaction of acetone with trihalomethyl ketones by usingN-(8-quinolinesulfonyl)prolinamide as an organocatalyst. The MO calculations elucidate that the hydrogen bonding between the sulfonimide proton and the 8-quinolyl nitrogen atom plays an important role in exerting the enantioselectivity of the reaction.
A method is disclosed for the control of nematodes in agricultural crops which comprises applying to the situs of infestation a compound of the formula
wherein Xl and X2 are each halogen atoms; R1 is hydrogen, lower alkyl, or di(lower)alkyl phosphate; each R is hydrogen, halogen, lower alkyl or nitro; and n is 0, 1, or 2. Preparation and nematicidal utility for the compounds are described and exemplified. When R1 is other than hydrogen or at least one R on the thiophene ring is nitro, advantageously at the 3 or 5 position of the thiophene ring, the compounds of the above formula are novel.