Diastereoselective Synthesis of N-Protected β-Amino-α-hydroxyacids (Norstatines) from Urethane N-Carboxyanhydrides (UNCAs)

Propargylic Alcohol ◽

β-Amino-α-hydroxyacids (norstatines) are prepared from urethane N-protected carboxyanhydrides (UNCAs); the key step is the diastereoselective reduction of a keto-acetylenic compound, which lead is, with syn diastereoselectivity, to the corresponding propargylic alcohol.

ChemInform Abstract: Highly Diastereoselective Reduction of γ-Keto Amides: Diastereoselective Synthesis of γ-Butyrolactones with Contiguous Chiral Centers.

ChemInform ◽

10.1002/chin.200014088 ◽

2010 ◽

Vol 31 (14) ◽

pp. no-no

Author(s):

Masami Satoh ◽

Sakurako Washida ◽

Sawako Takeuchi ◽

Morio Asaoka

Keyword(s):

Chiral Centers ◽

Highly Diastereoselective Reduction of g-Keto Amides: Diastereoselective Synthesis of g-Butyrolactones with Contiguous Chiral Centers

Heterocycles ◽

10.3987/com-99-s14 ◽

2000 ◽

Vol 52 (1) ◽

pp. 227 ◽

Cited By ~ 3

Author(s):

Morio Asaoka ◽

Masami Satoh ◽

Sakurako Washida ◽

Sawako Takeuchi

Keyword(s):

Chiral Centers ◽

Diastereoselective synthesis of β-amino alcohols with two or three chiral centers.

Tetrahedron Letters ◽

10.1016/s0040-4039(01)94542-3 ◽

1979 ◽

Vol 19 (15) ◽

pp. 1355-1356

Author(s):

R Haro-Ramos

Keyword(s):

Amino Alcohols ◽

Chiral Centers

1604096: CeO2 nanoparticles: a robust and reusable heterogeneous catalyst for the diastereoselective synthesis of β-acetamido esters – ESI

Journal of Chemical Research ◽

10.3184/174751916x14683300159522 ◽

2016 ◽

Keyword(s):

Heterogeneous Catalyst ◽

Ceo2 Nanoparticles ◽

Diastereoselective Synthesis

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

Current Organic Chemistry ◽

10.2174/1385272822666190924182538 ◽

2019 ◽

Vol 23 (16) ◽

pp. 1778-1788 ◽

Cited By ~ 5

Author(s):

Gurpreet Kaur ◽

Arvind Singh ◽

Kiran Bala ◽

Mamta Devi ◽

Anjana Kumari ◽

...

Keyword(s):

Room Temperature ◽

Biologically Active ◽

Environmentally Benign ◽

Substituted Anilines ◽

Reaction Conditions ◽

Naturally Occurring ◽

Acid Catalyzed ◽

Reaction Media ◽

Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

Diastereoselective Synthesis of Novel Optically Active Five Membered O- and N-heterocyclic Compounds

Letters in Organic Chemistry ◽

10.2174/157017812800221744 ◽

2012 ◽

Vol 9 (2) ◽

pp. 81-88 ◽

Cited By ~ 1

Author(s):

Ervin Kovacs ◽

Ferenc Farkas ◽

Angelika Thurner ◽

Aron Szollosy ◽

Ferenc Faigl

Keyword(s):

Heterocyclic Compounds ◽

Optically Active ◽

Diastereoselective Synthesis

Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

Current Organocatalysis ◽

10.2174/2213337207666201207212540 ◽

2020 ◽

Vol 07 ◽

Author(s):

Christian Trapp ◽

Corinna Schuster ◽

Chris Drewniok ◽

Dieter Greif ◽

Martin Hofrichter

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Selective Reduction ◽

Reducing Agents ◽

Relative Configuration ◽

Curtius Rearrangement ◽

Keto Esters ◽

Hydroxy Esters ◽

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.