124224-04-0Relevant articles and documents
Sodium percarbonate: A multifunctional reagent for the preparation of optically active 4-hydroxy-Δ2- isoxazolines
Liu, Jinchu,Eddings, Alicia,Wallace, Richard H.
, p. 6795 - 6798 (1997)
In this letter we report a general method for the preparation of optically active 4-hydroxy-Δ2-isoxazolines. This one-pot method employs sodium percarbonate for nitrile oxide generation, oxidation of the intermediate boronic ester substituted Δ2-isoxazoline, and cleavage of the chiral auxiliary from the final product.
Stereoselective α-Hydroxylation of Amides Using Oppolzer's Sultam as Chiral Auxiliary
Zhang, Lumin,Zhu, Lili,Yang, Jun,Luo, Jisheng,Hong, Ran
, p. 3890 - 3900 (2016)
An Oppolzer's sultam-based highly stereoselective α-hydroxylation of amides was developed to deliver the desired products in good yield and excellent diastereoselectivity (>20/1). The generally crystalline products and the recyclability of the chiral auxiliary illustrate the practicability and scalability of the current approach.
Efficacious preparation of Oppolzer's glycylsultam via the Delepine reaction
Isleyen, Alper,Gonsky, Carolyn,Ronald, Robert C.,Garner, Philip
, p. 1261 - 1264 (2009)
A new preparative route to Oppolzer's glycylsultam, the 'NC' component in the asymmetric [C+NC+CC] coupling reaction leading to functionalized pyrrolidines, is described. The synthesis features a novel application of the Delepine reaction, providing a saf
Diastereoselective Titanium Enolate Aldol Reaction for the Total Synthesis of Epothilones
Koch, Guido,Loiseleur, Olivier,Fuentes, Daniel,Jantsch, Andrea,Altmann, Karl-Heinz
, p. 3811 - 3814 (2002)
(Matrix Presented) The development of a highly diastereoselective addition of the titanium enolate derived from ketone 1 to aldehyde 2 offers an efficient entry to the total synthesis of the epothilone family. The new aldol process is robust and tolerates
Influence of norbornanone substituents on both the Wagner-Meerwein skeletal rearrangements under sulfonation conditions and the diastereoselectivity of the corresponding N,N′-bis-fumaroyl sultams in uncatalyzed Diels-Alder cycloadditions to cyclopenta-1,3-diene
Pia?tek, Anna,Chapuis, Christian
, p. 4247 - 4249 (2013)
The Wagner-Meerwein domino rearrangement of norbornanone skeletons, under sulfonation conditions, is strongly influenced by the absence of a gem-dimethyl moiety at C(7). As a result, sulfonation at C(10) is less efficient due to a divergent pathway in the intermediate double bond formation and/or isomerization. Furthermore, the absence of such a gem-dimethyl moiety in the corresponding norbornane[10,2]sultam derivatives, sterically influences the orientation of the SO(1) and SO(2) substituents, hence on the π-facial steric shielding of the thermodynamically more stable anti-s-cis N-alkenoyl dienophiles. As a consequence, their diastereoselective [4+2] cycloadditions to cyclopenta-1,3-diene, under nonchelating conditions, are not as efficient due to a less pseudo axial SO(1) and the consequent loss of pseudo C 2-symmetry.
A two-step synthesis of camphosultam
Capet,David,Bertin,Hardy
, p. 3323 - 3327 (1995)
Modifications of the known route to camphosultam led to an easy two-step process. The unique intermediate is simply isolated by filtration. The overall yield is 66% on a hundred gram scale.
12. Complete ?-Facial Stereoselectivity in the TiCl4-Mediated Cycloaddition of Cyclopentadiene to N,N-Fumaroyldi
Chapuis, Christian,Rzepecki, Piotr,Bauer, Tomasz,Jurczak, Janusz
, p. 145 - 150 (1995)
Under the co-operative influence of two prosthetic groups, and independent of the TiCl4 concentration, complete and constant diastereofacial ?-selection was achieved during the cycloaddition of cyclopentadiene to N,N'-fumaroyl-di((-)-1c); reactive conformations are discussed.
Asymmetric Induction on Copper(I) Chloride Catalyzed 1,4-Addition of Alkylmagnesium Chlorides to α,β-Disubstituted (E)-Enoylsultams and Subsequent Protonation
Oppolzer, Wolfgang,Kingma, Arend J.
, p. 1337 - 1345 (1989)
Successive treatment of conjugated N-enoylsultams 2 with alkyl Grignard reagents/CuCl and aq.NH4Cl solution generated selectively two stereogenic centers at C(α) and C(β) providing, after flash chromatography and crystallization, acylsultams 5 in high purity.Mild cleavage afforded the recovered sultam auxiliary 1 and enantiomerically pure carboxylic acids 7.
L-(6,7-dimethoxy-4-coumaryl) alanine: An intrinsic probe for the labelling of peptides
Bennett, Fiona A.,Barlow, David J.,Dodoo, Alexander N.O.,Hider, Robert C.,Lansley, Alison B.,Lawrence, M. Jayne,Marriott, Christopher,Bansal, Sukhvinder S.
, p. 7449 - 7452 (1997)
The asymmetric synthesis, spectral properties and incorporation into solid phase peptide synthesis are described for L-(6,7-dimethoxy-4-coumaryl)alanine (Dca). Dca has great utility as a specific and highly sensitive intrinsic probe for fluorescence labelling and quantitation of peptides and proteins.
Asymmetric synthesis of sultams and sulfonamides via diastereoselective reduction of N-sulfonylimines
Davis, Franklin A.,Zhou, Ping,Chen, Bang-Chi
, p. 85 - 91 (1996)
The diastereoselective reduction of both cyclic and acyclic camphor sulfonylimines was investigated. With cyclic camphor sulfonylimines 1, reduction using NaBH4 in methanol afforded the corresponding camphorsultams 2 in 92-95% yield as single d
