198547-74-9Relevant academic research and scientific papers
Visible-Light Mediated Hydrosilylative and Hydrophosphorylative Cyclizations of Enynes and Dienes
Chen, Xiaoyun,Hou, Hong,Shi, Yaocheng,Xu, Yue,Yan, Chaoguo,Yang, Haibo,Zhu, Shaoqun
supporting information, (2020/03/04)
Described herein is a visible-light mediated intermolecular radical cyclization approach to access heterocycles. Heteroatom radicals, such as silicon and phosphorus atom radicals, were generated via direct hydrogen atom abstraction by the photoexcited catalyst species with hydro-silanes and phosphine oxides. The radical addition/cyclization/HAT (hydrogen atom transfer) reaction sequences of 1,6-enynes and 1,6-dienes were highly efficient delivering the desired heterocycles in good yields.
Palladium-catalyzed double-bond migration of unsaturated hydrocarbons accelerated by tantalum chloride
Murai, Masahito,Nishimura, Kengo,Takai, Kazuhiko
supporting information, p. 2769 - 2772 (2019/03/23)
The operationally simple palladium-catalyzed double-bond migration without heteroatom-containing coordinating functional groups is described. Addition of TaCl5 as a second catalyst greatly enhanced the migration efficiency to provide β-alkylsty
BACTERIAL EFFLUX PUMP INHIBITORS
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Paragraph 0273-0274, (2016/10/11)
Disclosed herein are compounds of formula I: and salts thereof. Also disclosed are compositions comprising of compounds of formula I and methods using compounds of formula I.
The role of achiral pyrazolidinone templates in enantioselective Diels-Alder reactions: Scope, limitations, and conformational insights
Sibi, Mukund P.,Stanley, Levi M.,Nie, Xiaoping,Venkatraman, Lakshmanan,Liu, Mei,Jasperse, Craig P.
, p. 395 - 405 (2007/10/03)
We have evaluated the role of achiral pyrazolidinone templates in conjunction with chiral Lewis acids in room temperature, enantioselective Diels-Alder cycloadditions. The role of the fluxional N(1) substituent was examined, with the bulky 1-naphthylmethyl group providing enantioselectivities up to 99% ee, while templates with smaller fluxional groups gave lower selectivities. High selectivities were also observed in reactions of 7d with chiral Lewis acids derived from relatively small chiral ligands, suggesting the pyrazolidinone templates are capable of relaying stereochemical information from the ligand to the reaction center. Lewis acids capable of adapting square planar geometries, such as Cu(OTf)2, Cu(ClO4)2, and Pd(ClO4)2, were found to be particularly effective at providing high selectivities. Additionally, substitution at the C-5 position of the pyrazolidinone templates has been shown to be critical for optimal selectivity. Reactions of the optimal pyrazolidinone appended with a number of common dienophiles and various dienes demonstrate the utility of this achiral template. Furthermore, catalytic loadings could be lowered to 2.5 mol % with essentially no loss in selectivity, π-π interactions were evaluated as a means to explain the unusually high selectivity observed at room temperature. Finally, non-C2-symmetric ligands were employed as a test to determine if chiral relay was operative.
Exo Selective Enantioselective Nitrone Cycloadditions
Sibi, Mukund P.,Ma, Zhihua,Jasperse, Craig P.
, p. 718 - 719 (2007/10/03)
We have developed a novel method for accessing exo adducts with high enantioselectivity in nitrone cycloadditions to enoates. Pyrazolidinones proved to be effective achiral templates in the cycloadditions, providing exo adducts typically in >15:1 selectivity and 90-98% ee. The use of Lewis acids that form square planar complexes, such as copper triflate, was important for obtaining high exo selectivity. Copyright
Reaction of trithiazyl trichloride with active methylene compounds
Duan, Xiao-Guang,Duan, Xiao-Lan,Rees, Charles W.
, p. 2831 - 2836 (2007/10/03)
Activated allylic compounds react with trithiazyl trichloride, (NSCl)3, to give 1,2,5-thiadiazoles 1 and isothiazoles 2. An allylic 2-substituent normally prevents formation of an aromatic 1,2,5-thiadiazole, and isothiazole formation becomes the major pathway. Simple allylic compounds are not very reactive towards (NSCl)3 but a terminal electron withdrawing group (CO2Et) enhances the reactivity. With unsymmetrical allylic compounds, isothiazole formation is regiospecific placing the more electron withdrawing group adjacent to the ring sulfur. 1,3-Diketones give 3-acyl-1,2,5-thiadiazoles; unsymmetrical 1,3-diketones give these thiadiazoles regiospecifically, explicable by cyclisation of an intermediate onto the more reactive carbonyl group. 1,4-Diketones give 3,4-diacyl-1,2,5-thiadiazoles; thus 1,2-dibenzoyl-ethane,-echene and -ethyne all give 3,4-dibenzoylthiadiazole (40-44%). Many of these trithiazyl trichloride reactions provide attractive one-step routes to 1,2,5-thiadiazoles and isothiazoles.
