125872-62-0Relevant academic research and scientific papers
Strong acid-catalyzed electrophilic ring expansion of oxetanes and sulfoxonium ylides
Xie, Wenlai,Xu, Jiaxi,Yuan, Wenhao
, (2021/06/28)
A strong protic acid-catalyzed electrophilic ring expansion of oxetanes into trans-2,3-disubstituted tetrahydrofuran derivatives using sulfoxonium ylides has been developed. This reaction produces functionalized trans-2,3-disubstituted tetrahydrofuran derivatives stereospecifically by using safe and stable sulfoxonium ylides without metal catalysts and the protection of inert gas.
Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades
Das, Pradipta,Delost, Michael D.,Qureshi, Munaum H.,Bao, Jianhua,Fell, Jason S.,Houk, Kendall N.,Njardarson, Jon T.
supporting information, p. 5793 - 5804 (2021/05/07)
We report a dramatic effect on product outcomes of the lithium ion enabled amino-Cope-like anionic asymmetric cascade when different γ-dienolate heteroatom substituents are employed. For dienolates with azide, thiomethyl, and trifluoromethylthiol substituents, a Mannich/amino-Cope/cyclization cascade ensues to form chiral cyclohexenone products with two new stereocenters in an anti-relationship. For fluoride-substituted nucleophiles, a Mannich/amino-Cope cascade proceeds to afford chiral acyclic products with two new stereocenters in a syn-relationship. Bromide- and chloride-substituted nucleophiles appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent, with a lithium counterion being essential in combination with etheral solvents such as MTBE and CPME. By altering the geometry of the imine double bond from E to Z, the configurations at the R1 and X stereocenters are flipped. Mechanistic, computational, substituent, and counterion studies suggest that these cascades proceed via a common Mannich-product intermediate, which then proceeds via either a chair (X = N3, SMe, or SCF3) or boat-like (X = F, Cl, or Br) transition state to afford amino-Cope-like products or β-lactam in the case of X = NO2.
Integrating Allyl Electrophiles into Nickel-Catalyzed Conjunctive Cross-Coupling
Derosa, Joseph,Engle, Keary M.,Gallagher, Timothy J.,Li, Zi-Qi,Liu, Peng,Tran, Van T.
supporting information, p. 7029 - 7034 (2020/03/23)
Allylation and conjunctive cross-coupling represent two useful, yet largely distinct, reactivity paradigms in catalysis. The union of these two processes would offer exciting possibilities in organic synthesis but remains largely unknown. Herein, we repor
Synthesis of Allylsilanes via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Allyl Alcohols
Yang, Bo,Wang, Zhong-Xia
supporting information, p. 7965 - 7969 (2019/10/19)
NiCl2(PMe3)2-catalyzed reaction of allyl alcohols with silylzinc reagents, including PhMe2SiZnCl, Ph2MeSiZnCl, and Ph3SiZnCl, was performed, achieving allylsilanes in high yields. Aryl- and heteroaryl-substituted allyl alcohols, (E)-3-arylprop-2-en-1-ols, 1-aryl-prop-2-en-1-ols, and (E)-1-phenylpent-1-en-3-ol can be employed in the transformation. A range of functional groups as well as heteroaryl groups were tolerated. Reaction exhibited high regioselectivity and E/Z-selectivity when 1- or 3-aryl-substituted allyl alcohols were used as the substrates. Reaction of chiral allyl alcohol, (S,E)-1-phenylpent-1-en-3-ol, yielded a configuration-inversion product (R,E)-dimethyl(phenyl)(1-phenylpent-1-en-3-yl)silane.
A facile and efficient asymmetric synthesis of florfenicol
Li, Feng,Wang, Zhong-Hua,Zhao, Lei,Chen, Fen-Er
scheme or table, p. 2883 - 2885 (2012/01/11)
A facile and efficient enantioselective synthesis of flor-fenicol starting from commercially available 4-methylthiobenzaldehyde is described. Key features of the synthesis include a one-step oxidation of allyl and thioether groups in allylic alcohol to form (2S,3S)-epoxide under Sharpless epoxidation conditions and a highly efficient conversion of (1R,2R)-azide into amino alcohol via debenzylation and reduction of an azido moiety in one-pot operation. Georg Thieme Verlag Stuttgart. New York.
An efficient enantioselective synthesis of florfenicol via a vanadium-catalyzed asymmetric epoxidation
Li, Feng,Wang, Zhong-Hua,Zhao, Lei,Xiong, Fang-Jun,He, Qiu-Qin,Chen, Fen-Er
experimental part, p. 1337 - 1341 (2011/11/29)
An efficient and highly enantioselective synthesis of florfenicol 1 was achieved with 37% overall yield starting from commercially available 4-methylthiobenzaldehyde. A key feature of the synthesis is the vanadium-catalyzed asymmetric epoxidation of allylic alcohol 5 with aq tert-butyl hydroperoxide to form (2S,3S)-epoxide 6.
Synthesis and antifungal activities of R-102557 and related dioxane- triazole derivatives
Oida, Sadao,Tajima, Yawara,Konosu, Toshiyuki,Nakamura, Yoshie,Somada, Atsushi,Tanaka, Teruo,Habuki, Shinobu,Harasaki, Tamako,Kamai, Yasuki,Fukuoka, Takashi,Ohya, Satoshi,Yasuda, Hiroshi
, p. 694 - 707 (2007/10/03)
Novel triazole compounds with a dioxane ring were synthesized. Condensation of the diol precursor 10 with various aromatic aldehydes 11 - 13 under acidic conditions afforded a series of dioxane-triazole compounds 14 - 16. The antifungal activities of the compounds 14 - 16 were evaluated in vivo in mice infection models against Candida and Aspergillus species. High activities were seen for the derivatives with one or two double bond(s) and an aromatic ring substituted with an electron-withdrawing group in the side chain. Among the derivatives, R-102557 (16R: Ar=4-(2,2,3,3- tetrafluoropropoxy)phenyl) showed excellent in vivo activities against Candida, Aspergillus and Cryptococcus species. It also showed high tolerance in a preliminary toxicity study in rats.
