131180-90-0Relevant academic research and scientific papers
(S)-2-Aryl-4,4-diphenyl-3,1,2-oxazaboro[3.3.0]octanes: Efficient catalysts for the asymmetric borane reduction of electron-deficient ketones
Liu, Han,Xu
, p. 68 - 72 (2006)
The obvious influence of electronic effects of ketones on the enantioselectivities was observed previously in the oxazaborolidine-catalyzed asymmetric borane reduction of ketones. On the basis of the catalytic reduction mechanism, the electronic effect of
Modular, Scalable Synthesis of Group A Streptogramin Antibiotics
Li, Qi,Seiple, Ian B.
, p. 13304 - 13307 (2017)
Streptogramin antibiotics are used clinically to treat multidrug-resistant bacterial infections, but their poor physicochemical properties and narrow spectra of activity have limited their utility. New methods to chemically modify streptogramins would enable structural optimization to overcome these limitations as well as to combat growing resistance to the class. Here we report a modular, scalable synthesis of group A streptogramin antibiotics that proceeds in 6-8 linear steps from simple chemical building blocks. We have applied our route to the synthesis of four natural products in this class including two that have never before been accessed by fully synthetic routes. We anticipate that this work will lead to the discovery of new streptogramin antibiotics that overcome previous limitations of the class.
Enantioselective synthesis of polyketide segments through vinylogous Mukaiyama aldol reactions
Simsek, Serkan,Kalesse, Markus
, p. 3485 - 3488 (2009)
The synthesis of polyketide segments through the vinylogous Mukaiyama aldol reaction is reported. The use of chiral oxazaborolidines allows using terminal substituted ketene acetals and provides access to extended segments and two new chiral centers.
Effect of the secondary reduction on the enantioselectivity and function of additives in the chiral oxazaborolidine-catalyzed asymmetric borane reduction of ketones
Liu, Han,Du, Da-Ming,Xu, Jiaxi
, p. 1067 - 1074 (2006)
The secondary reduction in the direct and oxazaborolidine-catalyzed asymmetric borane reduction of ketones was investigated by the use of GC/MS tracing titration and control experiments. The results indicate that the secondary reduction affects the enantioselectivity only in noncoordinated solvents at low temperature and not under the usual catalytic reduction conditions because the intermediate alkoxyborane is unstable and quickly converts to borane and dialkoxyborane. The function of an alcohol additive in the asymmetric borane reduction of ketones is to consume excess borane in the reduction system thus inhibiting noncatalytic reduction, which leads to increased enantioselectivity in the catalytic reduction.
Enantioselective Cyclopropanation/[1,5]-Hydrogen Shift to Access Rauhut-Currier Product
Kim, Seung Tae,Pandit, Rameshwar Prasad,Yun, Jaesook,Ryu, Do Hyun
supporting information, p. 213 - 217 (2021/01/09)
A Michael addition initiated cyclopropanation/[1,5]-hydrogen shift has been developed for the enantioselective synthesis of Rauhut-Currier products. The reaction of α-alkyl diazoesters and in situ generated o-quinone methides proceeds in the presence of c
PROCESS TO MAKE A SELECTIVE CATHEPSIN CYSTEINE PROTEASE INHIBITOR
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Page/Page column 20-21, (2020/02/23)
A method of preparing a compound of Formula (I) comprising reacting the compound of Formula (A) with a base and a compound of Formula (B) to yield a compound of Formula (C).
Enantioselective Strecker and Allylation Reactions with Aldimines Catalyzed by Chiral Oxazaborolidinium Ions
Kang, Ki-Tae,Park, Sang Hyun,Ryu, Do Hyun
supporting information, p. 6679 - 6683 (2019/09/12)
Chiral oxazaborolidinium ion (COBI)-catalyzed enantioselective nucleophilic addition reactions of aldimines using tributyltin cyanide and allyltributylstannane have been developed. Various α-aminonitriles and homoallylic amines were synthesized in high yi
Enantioselective synthesis of α-alkyl-β-ketoesters: Asymmetric Roskamp reaction catalyzed by an oxazaborolidinium ion
Gao, Lizhu,Kang, Byung Chul,Hwang, Geum-Sook,Ryu, Do Hyun
supporting information; experimental part, p. 8322 - 8325 (2012/09/08)
Breaking kamp: A catalytic route toward chiral α-alkyl-β- ketoesters using the title reaction of α-alkyl diazoester with aldehydes has been developed (see scheme). The reaction proceeds with high to excellent enantioselectivities and this methodology was applied to a concise two-step synthesis of the natural pheromone sitophilate. Copyright
Rational electronic tuning of CBS catalyst for highly enantioselective borane reduction of trifluoroacetophenone
Korenaga, Toshinobu,Nomura, Kenji,Onoue, Kazutaka,Sakai, Takashi
, p. 8624 - 8626 (2011/01/03)
α,α,α-Trifluoroacetophenone (2), which is susceptible to noncatalytic reduction by BH3, could be reduced to chiral alcohol up to 90% ee by using electronically tuned-CBS catalyst (1) with BH3. The enantioselectivities highly correlated with the differential orbital energies between 1-BH3 adduct and 2, which were calculated by DFT method.
Catalytic enantioselective 1,3-dipolar cycloadditions of alkyl diazoacetates with α,β-disubstituted acroleins
Gao, Lizhu,Hwang, Geum-Sook,Lee, Mi Young,Ryu, Do Hyun
supporting information; scheme or table, p. 5460 - 5462 (2009/12/08)
A catalytic route to highly functionalized chiral 2-pyrazolines by an asymmetric 1,3-dipolar cycloaddition reaction of ethyl diazoacetate with α-substituted and α,β-disubstituted acroleins has been developed; in the presence of chiral (S)-oxazaborolidiniu
