- Stereospecific Asymmetric Synthesis of Tertiary Allylic Alcohol Derivatives by Catalytic [2,3]-Meisenheimer Rearrangements
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Chiral acyclic tertiary allylic alcohols are very important synthetic building blocks, but their enantioselective synthesis is often challenging. A major limitation in catalytic asymmetric 1,2-addition approaches to ketones is the enantioface differentiation by steric distinction of both ketone residues. Herein we report the development of a catalytic asymmetric Meisenheimer rearrangement to overcome this problem, as it proceeds in a stereospecific manner. This allows for high enantioselectivity also for the formation of products in which the residues at the generated tetrasubstituted stereocenter display a similar steric demand. Low catalyst loadings were found to be sufficient and the reaction conditions were mild enough to tolerate even highly reactive functional groups, such as an enolizable aldehyde, a primary tosylate, or an epoxide. Our investigations suggest an intramolecular rearrangement pathway.
- Yu, Xin,Wannenmacher, Nick,Peters, René
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supporting information
p. 10944 - 10948
(2020/05/04)
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- 11-Step Total Synthesis of Teleocidins B-1-B-4
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A unified and modular approach to the teleocidin B family of natural products is presented that proceeds in 11 steps and features an array of interesting strategies and methods. Indolactam V, the known biosynthetic precursor to this family, was accessed through electrochemical amination, Cu-mediated aziridine opening, and a remarkable base-induced macrolactamization. Guided by a desire to minimize concession steps, the tactical combination of C-H borylation and a Sigman-Heck transform enabled the convergent, stereocontrolled synthesis of the teleocidins.
- Nakamura, Hugh,Yasui, Kosuke,Kanda, Yuzuru,Baran, Phil S.
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supporting information
p. 1494 - 1497
(2019/01/26)
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- An efficient DABCO-catalyzed Ireland-Claisen rearrangement of allylic acrylates
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A novel DABCO-catalyzed Ireland-Claisen [3,3]-rearrangement of allylic acrylates to give α-methylene-γ,δ-unsaturated carboxylic acids in the presence of an excess of TMSCl and DBU in refluxing acetonitrile was developed. The protocol provides an easy entry to α-methylene-γ, δ-unsaturated carboxylic acids from allylic alcohols in good yields. Georg Thieme Verlag Stuttgart.
- Li, Yunxia,Wang, Quanrui,Goeke, Andreas,Fráter, Georg
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p. 288 - 292
(2007/10/03)
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- Catalytic hydromagnesiation of 2-alkylbutadienes
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The effect of alkyl substituents in 2-alkylbutadienes on their hydromagnesiation with alkylmagnesium halides was studied. 2001 MAIK "Nauka/Interperiodica".
- Viktorov,Zubritskii
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p. 1773 - 1785
(2007/10/03)
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- Catalytic hydromagnesation of di- and polymethyl-substituted 1,3-butadienes
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Hydromagnesation of di- and polymethyl-substituted 1,3-butadienes with alkylmagnesium halides in the presence of Ni(PPh3)2Cl2 and NiPy4Cl2 was studied.
- Viktorov,Zubritskii
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p. 1755 - 1765
(2007/10/03)
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- Indole derivatives as 5-HT1-like agonists for use in migraine
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The present invention relates to 3,5-disubstituted indole compounds which are selective agonists which act on 5-hdroxytryptamine receptors useful in the treatment of migraine.
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- Cp2TiCl2-catalyzed grignard reactions. 2. Reactions with ketones and aldehydes
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The reaction of Grignard reagents with ketones or aldehydes in the presence of a catalytic amount of Cp2TiCl2 leads to the corresponding reduction products in high yields. Cp2TiH intermediate was proposed to account for this observation.
- Sato, Fumie,Jinbo, Takamasa,Sato, Masao
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p. 2171 - 2174
(2007/10/02)
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