- 'meso-Selective' functionalisation of N-benzyl-α-methylbenzylamine derivatives by α-lithiation and alkylation
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Lithiation and methylation of amide and carbamate derivatives of α-methylbenzylamine proceeds with high diastereoselectivity in favour of meso bis-α-methylbenzylamine derivatives. Carboxylation of the intermediate organolithium is also diastereoselective, and with N-Boc p-methoxy-α-methylbenzylamine as starting material, oxidative cleavage provides a new asymmetric route to phenylglycine. Other electrophiles give a range of stereochemical outcomes, apparently depending on the stereospecificity of their reactions with a pair of diastereoisomeric organolithiums of low to moderate configurational stability.
- Bragg, Ryan A,Clayden, Jonathan,Menet, Christel J
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- Nickel-catalyzed allylation of α-amido sulfones to form protected homoallylic amines
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The allylation of stable, protected imine precursors, α-amido sulfones, with allylic acetates to form homoallylic amines is catalyzed by nickel under mild reducing conditions. Aliphatic and aryl imines are tolerated, as are substituted allylic acetates. I
- Caputo, Jill A.,Naodovic, Marina,Weix, Daniel J.
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- Synthesis of Cyclic Guanidines Bearing N-Arylsulfonyl and N-Cyano Protecting Groups via Pd-Catalyzed Alkene Carboamination Reactions
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Palladium-catalyzed carboamination reactions of N-allylguanidines bearing cleavable N-cyano or N-arylsulfonyl protecting groups are described. The reactions afford cyclic guanidine products in good yield, and transformations of substrates bearing internal alkenes proceed with high diastereoselectivity. Deuterium labeling studies indicate these transformations proceed via anti-aminopalladation pathways.
- Peterson, Luke J.,Luo, Jingyi,Wolfe, John P.
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supporting information
p. 2817 - 2820
(2017/06/07)
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- The acid promoted Petasis reaction of organotrifluoroborates with imines and enamines
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The acid promoted addition of organotrifluoroborate salts to imine and enamine electrophiles is reported. Use of the pre-activated trifluoroboronate complex bypasses the need for α-hetero substitution on the electrophile component, greatly expanding the scope of the Petasis borono-Mannich reaction. A variety of vinyl, aromatic and heteroaromatic trifluoroborate salts undergo addition with good efficiency under mild reaction conditions. The reaction is amenable for use with a variety of carbamate protected imine and enamine electrophiles, achieving for the first time the effective coupling with aliphatic aldehydes.
- Carrera, Diane E.
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supporting information
p. 11185 - 11188
(2017/10/16)
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- Dual Catalytic Decarboxylative Allylations of α-Amino Acids and Their Divergent Mechanisms
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The room temperature radical decarboxylative allylation of N-protected α-amino acids and esters has been accomplished via a combination of palladium and photoredox catalysis to provide homoallylic amines. Mechanistic investigations revealed that the stability of the α-amino radical, which is formed by decarboxylation, dictates the predominant reaction pathway between competing mechanisms.
- Lang, Simon B.,O'Nele, Kathryn M.,Douglas, Justin T.,Tunge, Jon A.
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p. 18589 - 18593
(2016/01/25)
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- Pd(II)-catalyzed allylic C-H amination for the preparation of 1,2- and 1,3-cyclic ureas
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A general synthesis of 1,2- and 1,3-cyclic ureas is accomplished by intramolecular allylic C-H amination employing Pd(TFA)2/bis-sulfoxide as a catalyst. By careful modification of substrates and catalyst, a variety of 1,2-cyclic ureas are accessible from not previously employed terminal olefins substituted in allylic or vinylic positions. Furthermore, MS4A is found to be an effective additive for the synthesis of 1,3-cyclic ureas in good yields and excellent diastereoselectivities.
- Nishikawa, Yasuhiro,Kimura, Seikou,Kato, Yuri,Yamazaki, Natsuka,Hara, Osamu
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p. 888 - 891
(2015/03/18)
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- N -Boc amines to oxazolidinones via Pd(II)/bis-sulfoxide/br?nsted acid Co-catalyzed allylic C-H oxidation
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A Pd(II)/bis-sulfoxide/Br?nsted acid catalyzed allylic C-H oxidation reaction for the synthesis of oxazolidinones from simple N-Boc amines is reported. A range of oxazolidinones are furnished in good yields (avg 63%) and excellent diastereoselectivities (avg 15:1) to furnish products regioisomeric from those previously obtained using allylic C-H amination reactions. Mechanistic studies suggest the role of the phosphoric acid is to furnish a Pd(II)bis-sulfoxide phosphate catalyst that promotes allylic C-H cleavage and π-allylPd functionalization with a weak, aprotic oxygen nucleophile and to assist in catalyst regeneration.
- Osberger, Thomas J.,White, M. Christina
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supporting information
p. 11176 - 11181
(2014/08/18)
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- Allylation of n,n-acetal derivatives using allyl tin reagent in the presence of aluminum chloride
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Allylation of N,N-acetal derivatives proceeded efficiently using allyl tin regent in the presence of aluminum chloride, giving homoallylamines in good yields. This allylation was applied for N,S-acetals to give the corresponding homoallylamines.
- Sun, Xiaonan,Obu, Takanori,Kijima, Tatsuro,Murakami, Satoshi,Matsuba, Shigeru,Kusakari, Miho,Hatano, Bunpei
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p. 2395 - 2402
(2013/11/19)
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- A new method of synthesis of 6-substituted piperidine-2,4-diones from homoallylamines
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Mono- and dihomoallylamines serve as convenient precursors for the preparation of 6-substituted piperidine-2,4-diones. This transformation is based, on the one hand, on a simple and well-known halocyclocarbamation reaction proceeding by the addition of a
- Kuznetsov, Nikolai Yu.,Maleev, Victor I.,Khrustalev, Victor N.,Mkrtchyan, Anna F.,Godovikov, Ivan A.,Strelkova, Tatyana V.,Bubnov, Yuri N.
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p. 334 - 344
(2012/02/16)
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- A Hg(ClO4)2 3 3H2O Catalyzed sakurai-hosomi allylation of isatins and isatin ketoimines using allyltrimethylsilane
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It is reported that Hg(ClO4)2 3 3H2O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of isatins or isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the firs
- Cao, Zhong-Yan,Zhang, Yan,Ji, Cong-Bin,Zhou, Jian
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supporting information; experimental part
p. 6398 - 6401
(2012/02/02)
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- A general and mild copper-catalyzed three-component synthesis of protected homoallyl amines
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A mild and highly efficient copper-catalyzed, one-pot, three-component reaction is developed for the synthesis of homoallyl amines. Reaction of an aldehyde, a carbamate, and allyltrimethylsilane in the presence of 5 mol % Cu(OTf)2 furnishes the corresponding protected homoallylic amines in good to excellent yields.
- Pasunooti, Kalyan Kumar,Leow, Min Li,Vedachalam, Seenuvasan,Gorityala, Bala Kishan,Liu, Xue-Wei
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scheme or table
p. 2979 - 2981
(2009/08/09)
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- Bismuth triflate-catalyzed addition of allylsilanes to N- alkoxycarbonylamino sulfones: Convenient access to 3-Cbz-protected cyclohexenylamines
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Bismuth triflate was found to be an efficient catalyst in the Sakurai reaction of allyltrimethylsilanes with N-alkoxycarbonylamino sulfones. The reaction proceeded smoothly with a low catalyst loading of Bi(OTf) 3·4H2O (2-5 mol%) to afford the corresponding protected homoallylic amines in very good yields (up to 96%). A sequential allylation reaction followed by ring-closing metathesis delivers 6-8 membered 3-Cbz-protected cycloalkenylamines.
- Ollevier, Thierry,Li, Zhiya
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supporting information; experimental part
p. 3251 - 3259
(2010/04/24)
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- Facile allylation of N-Boc and N-Cbz imines with allyltrichlorosilane promoted by DMF
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Facile allylation of various N-Boc and N-Cbz imines with allyltrichlorosilane has been effected using N,N-dimethylformamide (DMF) as the activator. The N-Boc and N-Cbz homoallylic amines were obtained in good to high yields under mild conditions. Copyrigh
- Wu, Pengcheng,Sun, Jian
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p. 1003 - 1010
(2008/09/18)
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- Phosphomolybdic acid-catalyzed efficient three-component reaction: A facile synthesis of protected homoallylic amines
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A new and efficient phosphomolybdic acid (H3PMo 12O40)-catalyzed three-component reaction of aldehydes, carbamate and allyltrimethylsilane to yield the corresponding protected homoallylic amines in good yields is described.
- Smitha,Miriyala, Bruhaspathy,Williamson, John S.
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p. 839 - 841
(2007/10/03)
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- Highly diastereoselective and enantioselective preparation of homoallylic amines: Application for the synthesis of β-amino acids and γ-lactams
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Reactions of N-silyl- and N-aluminoimines with B- allyldiisopinocampheylborane in the presence of methanol, followed by oxidative workup furnished homoallylic amines in good yields and high ee. A 11B NMR spectroscopy study revealed that the reactions do not proceed, even at room temperature, unless a molar equivalent of water or methanol is added. The first reagent-controlled asymmetric crotylboration and alkoxyallylboration of aldimines furnishing β-methyl or βalkoxy homoallylic amines in very high diastereoselectivity and enantioselectivity are reported herein. Crotylboration and alkoxyallylboration of imines proceed only with the "allyl"-boron "ate" complexes, instead of the "allyl"-dialkylboron reagents used with aldehydes. The addition of methanol is necessary for these reactions as well. Application of this methodology for the conversion of representative nitriles to β-amino acids in two steps has been described. Additionally, a procedure for the preparation of chiral δ-amino alcohols and γ-lactams from nitriles is also reported.
- Ramachandran, P. Veeraraghavan,Burghardt, Thomas E.
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p. 4387 - 4395
(2007/10/03)
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- Highly efficient three-component synthesis of protected homoallylic amines by bismuth triflate-catalyzed allylation of aldimines
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Bismuth triflate catalyzes the allylation of a variety of in situ generated protected aldimines using aldehydes, primary carbamates, and allyltrimethylsilane in a three-component reaction. The reaction proceeds rapidly and affords the corresponding protected homoallylic amine in good yield (up to 86%). Scope and limitations of the aldehyde and carbamate components are reported.
- Ollevier, Thierry,Ba, Tuya
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p. 9003 - 9005
(2007/10/03)
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- One-pot synthesis of protected homoallyl amines
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An efficient one-pot procedure for the synthesis of protected homoallyl amines from aldehydes or aldehyde acetals, carbamates and allyltrimethylsilane under influence of borontrifluoride etherate was developed. Scope and limitations of the aldehyde and carbamate components are reported.
- Veenstra, Siem J.,Schmid, Priska
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p. 997 - 1000
(2007/10/03)
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