- Overriding effect of temperature over reagent and substrate size for boron-mediated aldol reaction of methyl phenylacetate
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The enolization temperature overrides all other aspects, including the sterics of the alkyl group of the boron reagent and the alkoxy group of the ester during the enolboration-aldolization of phenylacetates. This study has led to the first n-Bu2/su
- Ramachandran, P. Veeraraghavan,Chanda, Prem B.
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supporting information
p. 5886 - 5888
(2013/10/21)
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- Enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates via boron-mediated asymmetric aldol reaction
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A reagent-controlled, diastereo- and enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates has been achieved by the proper choice of solvent, temperature, alkoxy group, and amine for the diisopinocampheylboron-mediated asymmetric enolization-aldolization of phenylacetates. The pure diastereomers can be readily separated by column chromatography.
- Ramachandran, P. Veeraraghavan,Chanda, Prem B.
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supporting information
p. 3152 - 3154
(2013/06/05)
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- An efficient cobalt(I)-catalysed reformatsky reaction using α-chloro esters
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An efficient cobalt(I)-catalysed Reformatsky reaction using α-chloro esters has been developed. The catalyst is prepared by reducing the cobalt(II) chloride (5%)/1,2-bis(diphenylphosphino)ethane (dppe)(5%)/zinc iodide (10%) system with zinc metal in acetonitrile in the presence of both the α-chloro ester and the carbonyl compound; good to excellent conversions to β-hydroxy esters are obtained at room temperature in 2.5 h.
- Lombardo, Marco,Gualandi, Alessandra,Pasi, Filippo,Trombini, Claudio
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p. 465 - 468
(2008/02/08)
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- Enolboration. 6. Dicyclohexyliodoborane, a Versatile Reagent for the Stereoselective Synthesis of Either Z or E Enolates from Representative Esters
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A smooth, rapid, quantitative, and highly stereoselective synthesis of either Z or E enolates from representative esters has been achieved with dicyclohexyliodoborane, Chx2BI, in the presence of a suitable tertiary amine, such as triethylamine or N,N-diis
- Ganesan, Kumaraperumal,Brown, Herbert C.
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p. 2336 - 2340
(2007/10/02)
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- Carbon-Carbon Bond-Forming Reactions Using Cerium Metal or Organocerium(III) Reagents
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Carbon-carbon bond-forming reactions using cerium metal or organocerium(III) reagents have been investigated.Cerium amalgam is an effective reagent for the chemoselective preparation of homoallylic alcohols from allyl halides and carbonyl compounds.These same reagent can also be satisfactorily employed for the Reformatsky-type reaction of α-halo esters with carbonyl compounds.It has been shown that organocerium(III) reagents are conveniently generated by the reaction of organolithiums with cerium(III)iodide or cerium(III)chloride.The reagents are less basic thanorganolithiums or Grignard reagents, and they react cleanly at -78 to -65 deg C with various carbonyl compounds to afford the addition products in high yields, even though the substrates are susceptible to enolization or metal-halogen exchange with simple organolithiums.The same reagents react also with α,β-unsaturated compounds to yield 1,2-addition products in high selectivity.
- Imamoto, Tsuneo,Kusumoto, Tetsuo,Tawarayama, Yoshinori,Sugiura, Yasushi,Mita, Takeshi,et al.
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p. 3904 - 3912
(2007/10/02)
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- A NEW METHOD FOR THE SYNTHESIS OF β-HYDROXYESTERS BY USING METALLIC TIN
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Metallic tin or activated metallic tin, prepared by reduction of stannous chloride with lithium aluminum hydride, smoothly reacts with α-haloesters to yield tin enolates, which in turn react with carbonyl compounds under mild conditions to give, after hydrolysis, β-hydroxyesters in high yields.
- Harada, Taira,Mukaiyama, Teruaki
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p. 161 - 164
(2007/10/02)
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