- Silylium-Ion-Promoted (5+1) Cycloaddition of Aryl-Substituted Vinylcyclopropanes and Hydrosilanes Involving Aryl Migration
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A transition-metal-free (5+1) cycloaddition of aryl-substituted vinylcyclopropanes (VCPs) and hydrosilanes to afford silacyclohexanes is reported. Catalytic amounts of the trityl cation initiate the reaction by hydride abstraction from the hydrosilane, and further progress of the reaction is maintained by self-regeneration of the silylium ions. The new reaction involves a [1,2] migration of an aryl group, eventually furnishing 4- rather than 3-aryl-substituted silacyclohexane derivatives as major products. Various control experiments and quantum-chemical calculations support a mechanistic picture where a silylium ion intramolecularly stabilized by a cyclopropane ring can either undergo a kinetically favored concerted [1,2] aryl migration/ring expansion or engage in a cyclopropane-to-cyclopropane rearrangement.
- Bonetti, Vittorio,He, Tao,Klare, Hendrik F. T.,Oestreich, Martin,Wang, Guoqiang
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supporting information
p. 12186 - 12191
(2020/05/22)
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- B(C6F5)3-Catalyzed Hydrosilylation of Vinylcyclopropanes
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A hydrosilylation of vinylcyclopropanes (VCPs) catalyzed by the strong boron Lewis acid B(C6F5)3 is reported. For the majority of VCPs, little or no ring opening of the cyclopropyl unit is observed. Conversely, for VCPs with bulky R groups, such as ortho-substituted aryl rings or branched alkyl residues, ring opening is the exclusive reaction pathway. This finding is explained by the thwarted hydride delivery to a sterically shielded, β-silicon-stabilized cyclopropylcarbinyl cation intermediate.
- He, Tao,Long, Peng-Wei,Oestreich, Martin
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supporting information
p. 7383 - 7386
(2020/10/12)
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- Br?nsted acid mediated intramolecular cyclopropane ring expansion/[4 + 2]-cycloaddition
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A cascade reaction of 3-hydroxy-2-phenylisoindolin-1-one and cyclopropyl ketone has been developed via a Br?nsted acid-promoted ring-opening/intramolecular cross-cycloaddition/[4 + 2]-cycloaddition process. The developed methodology provides straightforward access to pentacyclic isoindolin-1-one derivatives under simple reaction conditions.
- Li, Jian,Zhu, Shangrong,Xu, Qiuneng,Liu, Li,Yan, Shenghu
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p. 10004 - 10008
(2019/12/23)
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- Mild Ring Contractions of Cyclobutanols to Cyclopropyl Ketones via Hypervalent Iodine Oxidation
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An iodine-mediated oxidative ring contraction of cyclobutanols has been developed. The reaction allows the synthesis of a wide range of aryl cyclopropyl ketones under mild and eco-friendly conditions. A variety of functional groups including aromatic or alkyl halides, ethers, esters, ketones, alkenes, and even aldehydes are nicely tolerated in the reaction. This is in contrast with traditional synthetic approaches for which poor functional group tolerance is often a problem. The practicality of the method is also highlighted by the tunability of iodine oxidation system. Specifically, combining the iodine(III) reagent with an appropriate base allows the reaction to accommodate a range of challenging electron-rich arene substrates. The facile scalability of this reaction is also exhibited herein. (Figure presented.).
- Sun, Yan,Huang, Xin,Li, Xiaojin,Luo, Fan,Zhang, Lei,Chen, Mengyuan,Zheng, Shiya,Peng, Bo
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p. 1082 - 1087
(2018/01/27)
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- AZETIDINE COMPOUNDS AS GRP119 MODULATORS FOR THE TREATMENT OF DIABETES, OBESITY, DYSLIPIDEMIA AND RELATED DISORDERS
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The present disclosure relates to azetidine compounds. The azetidine compounds are GPR119 modulators and useful for the prevention and/or treatment of diabetes, obesity, dyslipidemia and related disorders. The present disclosure furthermore relates to the use of azetidine compounds as active ingredients in pharmaceuticals, and pharmaceutical compositions comprising them.
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Paragraph 0259
(2018/09/12)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
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supporting information
p. 12337 - 12340
(2017/11/20)
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- DECARBOXYLATIVE CROSS-COUPLING AND APPLICATIONS THEREOF
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Methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. For example, methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. A method described herein, in some embodiments, comprises providing a reaction mixture including a photoredox catalyst, a transition metal catalyst, a coupling partner and a substrate having a carboxyl group. The reaction mixture is irradiated with a radiation source resulting in cross-coupling of the substrate and coupling partner via a mechanism including decarboxylation, wherein the coupling partner is selected from the group consisting of a substituted aromatic compound and a substituted aliphatic compound.
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Page/Page column 31; 32; 34
(2015/12/09)
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- Merging Photoredox and Nickel Catalysis: The Direct Synthesis of Ketones by the Decarboxylative Arylation of α-Oxo Acids
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The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners. This mild decarboxylative arylation can also be utilized to efficiently access medicinal agents, as demonstrated by the rapid synthesis of fenofibrate. The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners.
- Chu, Lingling,Lipshultz, Jeffrey M.,Macmillan, David W. C.
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supporting information
p. 7929 - 7933
(2015/06/30)
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- A cascade approach to fused indolizinones through Lewis acid-copper(i) relay catalysis
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A relay catalytic cascade process involving Lewis acid triggered ring-opening of cyclopropyl ketones with nitriles, the copper(i)-catalyzed Ritter process, and acid-promoted N-acyliminium ion cyclization is described, which efficiently provides thieno-, furano-, and benzo-indolizinones in moderate to good yields. The Royal Society of Chemistry 2013.
- Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3351 - 3353
(2013/06/04)
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula whereinW represents —C(=O)— or —CH(OH)—;R1 represents hydrogen or hydroxy;R2 represents hydrogen;R1 and R2 taken together form a second bond between the carbon atoms bearing R1 and R2;n is an integer of from 1 to 5;m is an integer 0 or 1;R3 is —COOH or —COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; andpharmaceutically acceptable salts and individual optical isomers thereof, with the proviso that where R1 and R2 are taken together to form a second bond between the carbon atoms bearing R1 and R2 or where R1 represented hydroxy, m is an integer 0.
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Page column 25-26
(2008/06/13)
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula whereinW represents —C(=O)— or —CH(OH)—;R1 represents hydrogen or hydroxy;R2 represents hydrogen;R1 and R2 taken together form a second bond between the carbon atoms bearing R1 and R2;n is an integer of from 1 to 5;m is an integer 0 or 1;R3 is —COOH or —COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; and pharmaceutically acceptable salts and individual optical isomers thereof,with the proviso that where R1 and R2 are taken together to form a second bond between the carbon atoms bearing R1 and R2 or where R1 represented hydroxy, m is an integer 0.
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Page column 24
(2010/01/30)
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula wherein W represents —C(═O)— or —CH(OH)—; R1represents hydrogen or hydroxy; R2represents hydrogen; R1and R2taken together form a second bond between the carbon atoms bearing R1and R2; n is an integer of from 1 to 5; m is an integer 0 or 1; R3is —COOH or —COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched; each of A is hydrogen or hydroxy; and pharmaceutically acceptable salts and individual optical isomers thereof, with the proviso that where R1and R2are taken together to form a second bond between the carbon atoms bearing R1and R2or where R1represented hydroxy, m is an integer 0.
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula wherein W represents -C(=O)- or -CH(OH)-; R1 represents hydrogen or hydroxy; R2 represents hydrogen; R1 and R2 taken together form a second bond between the carbon atoms bearing R1 and R2; n is an integer of from 1 to 5; m is an integer 0 or 1; R3 is -COOH or -COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; and pharmaceutically acceptable salts and individual optical isomers thereof, with the proviso that where R1 and R2 are ta to form a second bond between the carbon R1 and R2 or where R1 represented hydroxy integer 0.
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- Laser flash photolysis study of arylcyclopropylcarbenium ions: Cation stabilizing abilities of cyclopropyl and phenyl groups
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Arylcyclopropylcarbenium ions, Ar(c-Pr)CH+, were generated as transient intermediates by laser flash photolysis (LFP) of trans-2,3-diphenylaziridinimines of aryl cyclopropyl ketones in 2,2,2-trifluoroethanol (TFE). The carbocations are thought to arise by way of diazo compounds and carbenes. Rate constants for the unimolecular decay in TFE and for the bimolecular reaction with methanol in TFE were obtained for Ar(c-Pr)CH+ and for analogous arylphenylcarbenium ions, ArPhCH+. Within these series, the cation stabilizing abilities of cyclopropyl and phenyl groups are found to be similar in magnitude. However, cyclopropyl responds more strongly than phenyl to increasing electron demand. Hence cyclopropyl is superior to phenyl in cation stabilizing ability for Ar = Ph but inferior to phenyl for Ar = 4-MeOC6H4.
- Kirmse, Wolfgang,Krzossa, Birgit,Steenken, Steen
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p. 7473 - 7477
(2007/10/03)
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- Synthesis of Alkyl and Aryl Cyclopropyl Ketones
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A series of cyclopropyl ketones are prepared by reactions of organometallic compounds with cyclopropanecarboxylic acid derivatives and also by cyclization of γ-chloro ketones.
- Matveeva,Kvasha,Kurts
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- Vinyl Cations. 41. Influence of 4-Aryl and 4-Alkyl Substituents on the ?-Route Solvolyses of Homopropargyl Esters
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The four 4-substituted-homopropargyl tosylates and triflates 6b-e (R=phenyl, p-tolyl, anisyl, and cyclopropyl) have been synthesized and solvolyzed under various conditions, as have 2-cyclopropyl-1-cyclobutenyl triflate (11-OTf) and nonaflate (11-ONf).In addition, the solvolyses of pent-3-yn-1-yl tosylate (6a-OTs, R=methyl) and triflate (prepared previously) are reported.The ratios of C-3 ring to C-4 ring 3 ring/C4ring)> products are recorded for the reactions in various solvents.As expected, ring closure (kΔ) increases and solvent displacement (kS, SN2) decreases with decreasing nucleophilicity of solvent.Temperature effects are noted for the sovolyses of tosylates 6a-e in 100percent TFE buffered with Na2CO3 in which kΔ increases with increasing temperature.The result is explained by decomposition of the intimate ion pair with temperature, whereupon elimination to the enyne becomes smaller and ring closure (kΔ) increases at the expense of elimination.The possibility of intervention of nonclassical vinyl cations is discussed, as are other mechanistic implications.
- Collins, Clair J.,Hanack, Michael,Stutz, Herbert,Auchter, Gerhard,Schoberth, Winfried
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p. 5260 - 5268
(2007/10/02)
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