- Chromium-Catalyzed Linear-Selective Alkylation of Aldehydes with Alkenes
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We developed a chromium-catalyzed, photochemical, and linear-selective alkylation of aldehydes with alkylzirconium species generated in situ from a wide range of alkenes and Schwartz's reagent. Photochemical homolysis of the C-Zr bond afforded alkyl radicals, which were then trapped by a chromium complex catalyst to generate the alkylchromium(III) species for polar addition to aldehydes. The reaction proceeded with high functional group tolerance at ambient temperature under visible-light irradiation.
- Hirao, Yuki,Kanai, Motomu,Katayama, Yuri,Mitsunuma, Harunobu
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supporting information
(2020/11/18)
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- Highly enantioselective dynamic kinetic resolution of alkyl aryl carbinols carrying a trimethylsilyl group with a highly active lipoprotein lipase preparation
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Abstract The kinetic and dynamic kinetic resolution of alkyl aryl carbinols carrying a trimethylsilyl group with a highly active lipase preparation containing lipoprotein lipase, dextrin, and ionic surfactant 1 has been explored. It was found that all the trimethylsilyl-containing substrates were accepted by lipoprotein lipase-dextrin 1 (LPL-D1) with perfect enantioselectivity (E = >200). As a result, the dynamic kinetic resolution of these substrates with LPL-D1 in the presence of a Ru-based racemization catalyst provided single enantiomeric products (>99% ee) with good yields. Furthermore, the dynamic kinetic resolution products were readily desilylated or halodesilylated to yield enantiopure alkyl aryl carbinols. Thus a useful protocol for the highly enantioselective synthesis of alkyl aryl carbinols, particularly those carrying a long alkyl chain (C6-C10) has been established.
- Cho, Jeonghun,Lee, Jusuk,Park, Jaiwook,Kim, Mahn-Joo
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p. 840 - 845
(2015/08/18)
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- SUBSTITUTED GAMMA LACTAMS AS THERAPEUTIC AGENTS
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Therapeutic compounds, compositions, medicaments, and methods are disclosed herein.
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Page/Page column 29-30
(2009/10/31)
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- Indium-copper and indium-silver mediated Barbier-Grignard-type alkylation reaction of aldehydes using unactivated alkyl halides in water
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(Chemical Equation Presented) An efficient method has been developed for the Barbier-Grignard-type alkylation reaction of aldehydes (including aliphatic version) using unactivated alkyl halides in water in the presence of an In/CuI/I2 or In/AgI/I2 system. The reactions proceeded more efficiently in water than in organic solvent. In, CuI or AgI, and I 2 were all essential for the efficient progress of the reactions. A radical-type reaction mechanism was studied and proposed by using 4-pentenal as substrate.
- Shen, Zhi-Liang,Yeo, Yan-Lin,Loh, Teck-Peng
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p. 3922 - 3924
(2008/09/19)
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- SUBSTITUTED GAMMA LACTAMS AS THERAPEUTIC AGENTS
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Therapeutic compounds, compositions, medicaments, and methods are disclosed herein.
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Page/Page column 18
(2008/06/13)
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- SUBSTITUTED GAMMA LACTAMS AS THERAPEUTIC AGENTS
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A compound comprising Formula (I) or a pharmaceutically acceptable salt, prodrug, or a metabolite thereof is disclosed herein. Y, A, and B are as described herein. Methods, compositions, and medicaments related to these compounds are also disclosed.
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Page/Page column 66-67
(2008/06/13)
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- A new method for alkylation of aromatic aldehydes using alkylboron chloride derivatives in the presence of oxygen
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Reactions of aromatic aldehydes with alkylboron chloride derivatives in the presence of oxygen have been investigated. Dialkylboron chlorides react with aryl aldehydes to produce arylalkylmethanols in good to excellent yields. Under the same reaction conditions, alkylboron dichlorides lead to the formation of arylalkyl chlorides.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
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p. 3243 - 3248
(2007/10/03)
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- Alkylation of aromatic aldehydes with alkylboron chloride derivatives
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The reaction of aryl aldehydes with alkylboron chlorides has been investigated. Monoalkylboron dichlorides react with aryl aldehydes in hexane under reflux conditions to give a mixture of dichloroarylmethane and benzyl chloride. Under the same reaction conditions, dialkylboron chlorides lead to formation of a mixture of benzyl chloride and the chloroalkylation product. In the presence of a base such as 2,6-lutidine, the reactions of monoalkylboron dichlorides with aryl aldehydes yield small amounts of the desired alkylation products at room temperature. Dialkylboron chlorides react with aryl aldehydes in hexane in the presence of base to generate the corresponding arylalkylmethanols in good yields.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
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p. 1663 - 1670
(2007/10/03)
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- Novel anthracycline-spacer-β-glucuronide, -β-glucoside, and -β-galactoside prodrugs for application in selective chemotherapy
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A series of anthracycline prodrugs containing an immolative spacer was synthesized for application in selective chemotherapy. The prodrugs having the general structure anthracycline-spacer-β-glycoside were designed to be activated by β-glucuronidase or β-galactosidase. Prodrugs with -chloro, -bromo or -n-hexyl substituents on the spacer were synthesized as well as prodrugs containing a -β-glucuronyl, -β-glucosyl or -β-galactosyl carbamate specifier. The key step in the synthesis of all prodrugs is the highly β-diastereoselective addition reaction of the anomeric hydroxyl of a glycosyl donor to a spacer isocyanate resulting in the respective β-glycosyl carbamate pro-moieties. The resulting protected pro-moieties were coupled to an anthracycline. Prodrugs were evaluated with respect to activation rate by the appropriate enzyme and additionally, their IC50 values were determined. Optimal prodrugs in this study were at least 100- to 200-fold less toxic than their corresponding drug in vitro and were activated to the parent drug in a half-life time of approximately 2h. Copyright (C) 1999 Elsevier Science Ltd.
- Leenders, Ruben G. G.,Damen, Eric W. P.,Bijsterveld, Edward J. A.,Scheeren, Hans W.,Houba, Pieter H. J.,Van Der Meulen-Muileman, Ida H.,Boven, Epie,Haisma, Hidde J.
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p. 1597 - 1610
(2007/10/03)
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- Preparation and Properties of Tertiary p-Alkylarylphosphines containing Straight-chain Alkyl Groups
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A series of tris(p-alkylaryl)phosphines with straight-chain alkyl groups, P(p-C6H4-CnH2n+1)3 where n=2-9, have been prepared by reaction of phosphorus trichloride with the Grignard reagent derived from the corresponding p-bromoalkylbenzene.When n=2 and 3 the phosphines are crystalline solids, but for n>3 they are viscous oils up to n=9, which is a waxy solid.The phosphines have been characterised by microanalysis, and i.r., 1H and 31P n.m.r., and mass spectrometry.The p-substituted-arylphosphines are more sensitive than triphenylphosphine to air; aerial oxidation converts them exclusively into the corresponding phosphine oxides, in contrast to trialkylphosphines which are oxidised to a complex mixture of products.The complexing ability of the new phosphines (PAr3) is demonstrated by their ready displacement of 1,5-cyclo-octadiene (cod) from (M=Pd and Pt) to yield trans- and cis-, respectively.
- Franks, Stephen,Hartley, Frank R.
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p. 2233 - 2237
(2007/10/02)
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