Diastereoselective α-hydroxyamination of N-tert-butanesulfinyl imidates using nitrosoarenes is reported. A catalytic amount of base effectively promotes the hydroxyamination reaction of α-aryl-substituted imidates, and the resulting α-hydroxyamino imidates can be transformed into a range of synthetically useful intermediates.
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http://dx.doi.org/10.1021/acs.orglett.6b03835 | DOI Listing |
Org Lett
January 2025
School of Chemistry, Dalian University of Technology, 116024 Dalian, China.
This study presents the indium-mediated three-component radical Reformatsky-type allylation of --butanesulfinyl iminoester with 1,3-butadiene. This novel approach offers a rapid synthesis pathway to valuable homoallylic noncanonical amino acids, demonstrated with over 30 examples showing nice regio- and diastereoselectivity. Mechanism studies revealed that allylindium complexes served as key intermediates, formed through a single-electron reduction of allylic radicals by Indium species.
View Article and Find Full Text PDFOrg Lett
July 2024
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
The Rh(II)-catalyzed enantioselective -alkylation of sulfenamides with α-amide diazoacetates at 1 mol % catalyst loading to obtain sulfilimines in high yields and enantiomeric ratios of up to 99:1 is reported. The enantioenriched sulfilimine products incorporate versatile amide functionality poised for further elaboration to diverse sulfoximines with multiple stereogenic centers, including by highly diastereoselective sulfilimine and sulfoximine α-alkylation with alkylating agents and epoxides and by interconversion of the amide to --butanesulfinyl aldimines, followed by diastereoselective additions.
View Article and Find Full Text PDFJ Org Chem
May 2024
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
The stereoselective synthesis of vicinal amino alcohols derivatives from 1-substituted cyclopropanols and chiral --butanesulfinyl imines is described. Cyclopropanols are easily prepared from carboxylic esters upon reaction with ethylmagnesium bromide in the presence of titanium tetraisopropoxide and undergo carbon-carbon bond cleavage by means of diethylzinc to produce, upon base deprotonation, enolized zinc homoenolates, which react with chiral sulfinyl imines in a highly regio- and stereoselective manner.
View Article and Find Full Text PDFJ Org Chem
April 2024
School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China.
A stereocontrolled protocol was developed to construct less accessible fluorine-containing acyclic tetrasubstituted stereocenters bearing two sterically and electronically similar alkyl groups at the α-position of carbonyls. In this process, BuOK-promoted stereospecific α-deprotonation of α,α-disubstituted --butanesulfinyl ketimines or NH deprotonation of β,β-disubstituted enesulfinamides generates geometry-defined multisubstituted metalloenamines, followed by stereoselective electrophilic fluorination with the -fluoro ammonium salt of quinine, affording the acyclic α-fluorinated ketimines with excellent diastereoselectivities.
View Article and Find Full Text PDFThe --butanesulfinylimine group behaves as a suitable electron-withdrawing group in 1-azadienes, allowing the diastereoselective synthesis of densely substituted pyrrolidines by 1,3-dipolar cycloadditions (1,3-DCs) with azomethylene ylides. The use of AgCO as catalyst has allowed one to obtain a wide variety of proline derivatives with high regio- and diastereoselectivities. Subsequent efficient transformations provide valuable proline derivatives, some of which can be used as organocatalysts.
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