Benzotriazole-Mediated Conversions of Aromatic and Heteroaromatic Aldehydes to Functionalized Ketones
摘要:
Aromatic and heteroaromatic aldehydes reacted with benzotriazole and triethyl orthoformate in THF to give the corresponding alpha-(benzotriazol-1-yl)aryl ethyl ethers 7 in good yield. The novel acyl anion precursors 7 underwent smooth lithiation at the methine group followed by trapping with alkyl halides, aldehydes, ketones, and imines to yield the expected substituted intermediates of type 9, which were hydrolyzed under mild conditions without isolation. Benzaldehyde, methyl-, chloro-, and methoxy-substituted benzaldehydes, 1-naphthalenecarboxaldehyde, 2- and 3-furaldehydes, 2- and 3-thiophenecarboxaldehydes, and 2-pyridinecarboxaldehyde were all transformed in this manner into a variety of aryl and heteroaryl ketones with alkyl (10), alpha-hydroxyalkyl (12 and 13), alpha-aminoalkyl (14) and acyl(15) substituents.
Mannich Reactions of Carbohydrate Derivatives with Ketones To Afford Polyoxy-Functionalized Piperidines
作者:Lingaiah Maram、Fujie Tanaka
DOI:10.1021/acs.orglett.9b00105
日期:2019.2.15
Mannich reactions of carbohydrate derivatives with ketones that afford polyoxy-functionalized piperidines are reported. Ketone nucleophiles (enamines/enolates) were generated in the presence of the amines used for the formation of the iminium ions of sugar derivatives with or without an additive. Conditions to preferentially generate piperidine derivatives rather than tetrahydrofurans were identified
One‐Pot Synthesis of Quinoline Derivatives Directly from Terminal Alkynes
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Sequential Ruthenium(II) and Acid Catalysis
作者:Min Zhang、Thierry Roisnel、Pierre H. Dixneuf
DOI:10.1002/adsc.201000278
日期:2010.10.9
A convenient one-potsynthesis of 2,3-disubstituted, 2,3,6-trisubstituted, and 2,3,6,7-tetrasubstituted quinoline analoguesfrom terminal alkynes via sequential ruthenium(II) and para-toluenesulfonic acid (p-TSA) co-catalyzed reactions is described. The catalytic process is shown to take place first via intermediate formation of an allyl ketone and then addition of an aniline derivative to the allyl
aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant C═Cbondcleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible
highly efficient Pd/Xiang-Phos catalyzedenantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with up to 97 % ee. The sterically bulky and electron-rich (S,Rs)-NMe-X2 ligand is responsible for the excellent reactivities and enantioselectivities. The salient features of this
Copper-mediated oxysulfonylation of alkenyl oximes with sodium sulfinates: a facile synthesis of isoxazolines featuring a sulfone substituent
作者:Li-Jing Wang、Manman Chen、Lin Qi、Zhidong Xu、Wei Li
DOI:10.1039/c7cc00090a
日期:——
A novel and efficient Cu(OAc)2-mediated oxysulfonylation of alkenyl oximes with sodium sulfonates was developed. The reactions are easy to conduct, occur under mild conditions, and form a broad range of...