La catálisis homogénea enantioselectiva constituye un campo de enorme importancia por su potencial en procesos encaminados a la preparación de compuestos enantioméricamente puros o enriquecidos con aplicaciones comerciales (productos farmacéuticos, agroqu
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April 11, 2018 (v1)PublicationUploaded on: December 4, 2022
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June 3, 2022 (v1)Publication
An efficient, scalable and operationally simple one-pot, 2-step strategy for the nucleophilic formylation of trifluoromethyl ketones is presented. The key step is an unprecedented diaza-carbonyl-ene reaction of formaldehyde tert-butyl hydrazone and trifluoromethyl ketones under solvent-free conditions. This reaction proved to be very fast,...
Uploaded on: March 25, 2023 -
February 27, 2018 (v1)Publication
The unprecedented diaza-ene reaction of formaldehyde N-tert-butyl hydrazone with nitroalkenes can be efficiently catalyzed by an axially chiral bis-thiourea to afford the corresponding diazenes in good to excellent yields (60-96%) and moderate enantioselectivities, up to 84 : 16 er; additional transformation of diazenes into their tautomeric...
Uploaded on: December 5, 2022 -
April 20, 2022 (v1)Publication
The asymmetric 1,2-addition of formyl anion equivalents to carbonyl compounds is a powerful synthetic tool that ideally provide access to highly functionalizable a-hydroxy aldehydes in an enantioselective fashion. In this context, the nucleophilic character of formaldehyde hydrazones, together with their remarkable stability as monomeric...
Uploaded on: December 4, 2022 -
February 27, 2015 (v1)Publication
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Uploaded on: March 27, 2023 -
June 20, 2018 (v1)Publication
This Minireview summarizes strategies and developments regarding the use of hydrazones as reagents in asymmetric organocatalysis, their distinct roles in nucleophile–electrophile, cycloaddition, and cyclization reactions. The key structural elements governing the reactivity of these reagents in a preferred pathway will be discussed, as well as...
Uploaded on: March 25, 2023 -
November 28, 2022 (v1)Publication
A highly enantio- and diastereoselective thiourea-catalyzed dearomatization of isoquinolines employing N-tert-butylhydrazones as neutral α-azo carbanions and masked acyl anion equivalents has been developed. Experimental and computational data supports the generation of highly ordered complexes wherein the chloride behaves as a template for the...
Uploaded on: December 4, 2022 -
November 29, 2022 (v1)Publication
Catalysts generated by combinations of Pd(TFA)2and pyridine-hydrazone ligands have allowed the asymmetric 1,2-addition of aryl boronic acids toN-carbamoyl (Cbz and Fmoc) protected glyoxylate-derived hydrazones, yielding a-aryl a-hydrazino esters/amides in high enantioselectivities. Subsequent removal of the carbamoyl moiety affords key building...
Uploaded on: March 24, 2023 -
December 16, 2022 (v1)Publication
The nucleophilic addition of formaldehyde tert-butyl hydrazone to fluoromethyl ketones provides a valuable tool for the synthesis of highly functionalized β-hydroxy β-tri- and difluoromethyl diazenes. Excellent reactivities and moderate to good enantioselectivities (up to 90 % ee) were achieved by H-bonding activation exerted by tert-Leucine...
Uploaded on: March 24, 2023 -
December 16, 2022 (v1)Publication
The nucleophilic addition of formaldehyde tert-butylhydrazone to simple aldehydes (a formal hetero-carbonyl–ene reaction) can be performed with good reactivity and excellent enantioselectivity by virtue of the dual hydrogen-bonding activation exerted by amide–squaramide organocatalysts. The resulting hydroxydiazenes (azo alcohols) were isolated...
Uploaded on: March 24, 2023 -
February 21, 2018 (v1)Publication
The enantioselective organocatalytic Strecker-type reaction of aliphatic N,N-dialkylhydrazones is presented. Using trimethylsilyl cyanide (TMSCN) as the cyanide source, the reaction can be efficiently catalyzed by a tert-leucine-derived bifunctional thiourea to afford the corresponding hydrazino nitriles in good to excellent yields (50-96%) and...
Uploaded on: March 27, 2023 -
December 15, 2022 (v1)Publication
Catalysts generated by combinations of Pd(TFA)2 and enantiomerically pure pyridine-hydrazone ligands have been applied to the 1,4-addition of arylboronic acids to β-substituted cyclic enones, building all-carbon quaternary stereocenters in high yields and enantioselectivities (up to 93% ee). The developed methodology allows the efficient...
Uploaded on: March 24, 2023 -
November 10, 2022 (v1)Publication
The geometries and coordination properties of modular pyridineehydrazone N,N-ligands containing C2- symmetric trans-2,5-diphenylpyrrolidine and trans-2,5-diphenylpiperidine as the terminal dialkylamino units have been analyzed by X-ray diffraction analysis of [PdCl2(N,N)] complexes [(N,N)¼pyridine hy- drazone ligand]. In combination with...
Uploaded on: March 24, 2023 -
August 30, 2024 (v1)Publication
Catalysts generated by combinations of Pd(TFA)2 and pyridine-hydrazone ligands have been applied to 1,2 addition of arylboronic acids to aliphatic N-carbamoyl (Cbz) hydrazones, affording protected α- aryl monoalkylhydrazines with high enantioselectivities (37-99% ee). Subsequent removal of the benzyloxy carbonyl protecting group provides a...
Uploaded on: August 31, 2024 -
May 24, 2018 (v1)Publication
A series of peracylated glycosamine-derived thioureas have been synthesized and their behavior as bifunctional organocatalysts has been tested in the enantioselective nucleophilic addition of formaldehyde tert-butyl hydrazone to aliphatic α-keto esters for the synthesis of tertiary azomethyl alcohols. Using the...
Uploaded on: December 4, 2022