5469-33-0Relevant academic research and scientific papers
Desymmetrization by Asymmetric Copper-Catalyzed Intramolecular C-H Insertion Reactions of α-Diazo-β-oxosulfones
Brouder, Thomas A.,Slattery, Catherine N.,Ford, Alan,Khandavilli, U. B. Rao,Sko?epová, Eli?ka,Eccles, Kevin S.,Lusi, Matteo,Lawrence, Simon E.,Maguire, Anita R.
, p. 7543 - 7563 (2019)
Effective desymmetrization in copper-catalyzed intramolecular C-H insertion reactions of α-diazo-β-oxosulfones in the formation of fused thiopyran dioxides is described for the first time. The use of a copper-bis(oxazoline)-NaBARF catalyst complex system leads to formation of the major thiopyran dioxide stereoisomer with up to 98:2 dr and up to 98% ee. The effect of varying the bis(oxazoline) ligand, copper salt, and site of C-H insertion on both diastereo- and enantioselectivities of these intramolecular C-H insertion reactions has been investigated. Similarly, desymmetrization in the formation of a fused cyclopentanone proceeds with up to 64% ee. These results represent the highest enantioselectivity reported to date in a copper-mediated desymmetrization through C-H insertion.
Synthesis of Axially Chiral Anilides Enabled by a Palladium/Ming-Phos-Catalyzed Desymmetric Sonogashira Reaction
Yang, Bin,Yang, Junfeng,Zhang, Junliang
supporting information, p. 317 - 322 (2021/12/23)
Atropisomeric anilides are one of important C—N axially chiral compounds. Compared with the N-terminal functionalization to prepare such compounds, C-terminal functionalization strategies have been rarely reported. We describe herein an efficient synthesis of axially chiral anilides enabled by Pd-catalyzed desymmetric Sonogashira cross-coupling reactions with the use of a newly identified Ming-Phos. Moderate to high yields with high enantioselectivities (up to 98% ee) were obtained.
Formation, Alkylation, and Hydrolysis of Chiral Nonracemic N-Amino Cyclic Carbamate Hydrazones: An Approach to the Enantioselective α-Alkylation of Ketones
Huynh, Uyen,McDonald, Stacey L.,Lim, Daniel,Uddin, Md. Nasir,Wengryniuk, Sarah E.,Dey, Sumit,Coltart, Don M.
, p. 12951 - 12964 (2018/11/30)
The α-alkylation of ketones is a fundamental synthetic transformation. The development of asymmetric variants of this reaction is important given that numerous natural products, drugs, and related compounds exist as α-functionalized ketones or derivatives thereof. We previously reported our preliminary studies on the development of a new enantioselective ketone α-alkylation procedure using N-amino cyclic carbamate (ACC) auxiliaries. In comparison to other auxiliary-based methods, ACC alkylation offers a number of advantages and is both highly enantioselective and high yielding. Herein, we provide a full account of our studies on the enantioselective ACC ketone α-alkylation method.
NOVEL COMPOUND HAVING BONE METABOLISM INHIBITORY ACTIVITY AND METHOD FOR PRODUCING THE SAME
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Paragraph 0179, (2017/08/02)
PROBLEM TO BE SOLVED: To provide a novel compound having bone metabolism inhibitory activity, the compound having inhibitory activity on BMP signaling through the ALK2 receptor, and also having high pharmacological activity and high safety. SOLUTION: The
Phthalocyanines bearing bulky cycloalkylmethyl substituents on non-peripheral sites
Cammidge, Andrew N.,Tseng, Chiung-Hui,Chambrier, Isabelle,Hughes, David L.,Cook, Michael J.
supporting information; experimental part, p. 5254 - 5256 (2009/12/06)
Octasubstituted phthalocyanines bearing bulky (cyclopentyl)methyl- and (cyclohexyl)methyl-substituents in non-peripheral positions are prepared and characterised. The synthesis of the precursor phthalonitriles is achieved through nickel-catalysed cross-co
2-substituted-(2SR)-2-amino-2-((1SR,2SR)-2-carboxycycloprop-1- yl)glycines as potent and selective antagonists of group II metabotropic glutamate receptors. 1. Effects of alkyl, arylalkyl, and diarylalkyl substitution
Ornstein, Paul L.,Bleisch, Thomas J.,Arnold, M. Brian,Wright, Rebecca A.,Johnson, Bryan G.,Schoepp, Darryle D.
, p. 346 - 357 (2007/10/03)
In this paper, we describe the synthesis of a series of α-substituted analogues of the potent and selective group II metabotropic glutamate receptor (mGluR) agonist (1S,1'S,2'S)-carboxy-cyclopropylglycine (2, L-CCG 1). Incorporation of a substituent on the amino acid carbon converted the agonist 2 into an antagonist. All of the compounds were prepared and tested as a aeries of four isomers, i.e., two racemic diastereomers. We explored alkyl substitution, both normal and terminally branched; phenylalkyl and diphenylalkyl substitution; and a variety of aromatic and carbocyclic surrogates for phenyl. Affinity for group II mGluRs was measured using [3H]glutamic acid (Glu) binding in rat forebrain membranes. Antagonist activity was confirmed for these compounds by measuring their ability to antagonize (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid-induced inhibition of forskolin-stimulated cyclic-AMP in RGT cells transfected with human mGluR2 and mGluR3. We found that while alkyl substitution provided no increase in affinity relative to 2, phenylethyl and diphenylethyl substitution, as in 105 and 109, respectively, were quite beneficial. The affinity of 109 was further enhanced when the two aromatic rings were joined by an oxygen or sulfur atom to form the tricyclic xanthylmethyl and thioxanthylmethyl amino acids 113 and 114, respectively. Amino acid 113, with an IC50 of 0.010 μM in the [3H]Glu binding assay, was 52-fold more potent than 2, whose IC50 was 0.47 μM.
Photochemistry of Alkyl Halides. 9. Geminal Dihalides
Kropp, Paul J.,Pienta, Norbert J.
, p. 2084 - 2090 (2007/10/02)
The photobehavior of the geminal dihalides (diiodomethyl)cyclohexane (7), (bromoiodomethyl)cyclohexane (11), (dibromomethyl)cyclohexane (17), (diiodomethyl)cyclopentane (22), 3,3-dimethyl(diiodomethyl)cyclobutane (27), and 8,8-diiodo-2,6-dimethyl-2-octene (31) has been studied and compared with that previously observed for diiodomethane.In all solvents the corresponding vinyl halides (iodomethylene)cyclohexane (13), (bromomethylene)cyclohexane (21), (iodomethylene)cyclopentane (23), 3,3-dimethyl(iodomethylene)cyclobutane (28), or cis- and trans-3,7-dimethyl-1-iodo-1,6-octadiene (33) were obtained, which are thought to arise from α-halo cationic intermediate formed via initial light-induced homolytic cleavage of the carbon-iodine bond followed by electron transfer within the resulting caged radical pair, as shown in Schemes II and III.In the case of diiodide 31 competing intramolecular trapping of the α-iodo cation afforded in addition the cyclized isopulegyl iodide (34).In polar solvents the vinyl iodides were accompanied by the nonhalogenated products methylenecyclohexane (15), 1-methylcyclopentene (25), cyclohexene (26), 4,4-dimethylcyclopentene (29), and cis- and trans-carane (35), which are thought also to arise from the α-halo cationic intermediate. 1.1-Diiodo-2,2-dimethylpropane (1b) afforded 2-methyl-2-butene (6b).Except for carane (35) from diiodide 31 there was no detectable formation of cyclopropanes.In methanol the nucleophilic substitution products (dimethoxymethyl)cyclohexane (14), (dimethoxymethyl)cyclopentane (24), and 1,1-dimethoxy-2,2-dimethylpropane (30) were obtained.It is concluded that geminal dihalides undergo predominant, if not exclusive, photoreaction via initial clea vage of a single carbon-halogen bond in analogy with monohalides and that carbene intermediates are not formed.A similiar conclusion has been reached previously for diiodomethane in the photocyclopropanation of alkenes.
Iodo-azide Adducts of Exocyclic Alkenes; Structure and Solvolysis
Cambie, Richard C.,Jurlina, Jeffrey L.,Rutledge, Peter S.,Woodgate, Paul D.
, p. 315 - 326 (2007/10/02)
The addition of iodine(I) azide, generated from sodium azide-iodine(I) chloride in acetonitrile, to 3-methylene-5α-androstane (1) and to 1-methylene-4-t-butylcyclohexane (42) in the presence of oxygen is regioselective and gives adducts containing an iodo
