- B(C6F5)3-Catalyzed Hydrosilylation of Vinylcyclopropanes
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A hydrosilylation of vinylcyclopropanes (VCPs) catalyzed by the strong boron Lewis acid B(C6F5)3 is reported. For the majority of VCPs, little or no ring opening of the cyclopropyl unit is observed. Conversely, for VCPs with bulky R groups, such as ortho-substituted aryl rings or branched alkyl residues, ring opening is the exclusive reaction pathway. This finding is explained by the thwarted hydride delivery to a sterically shielded, β-silicon-stabilized cyclopropylcarbinyl cation intermediate.
- He, Tao,Long, Peng-Wei,Oestreich, Martin
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supporting information
p. 7383 - 7386
(2020/10/12)
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- Synergistic Photoredox/Nickel Coupling of Acyl Chlorides with Secondary Alkyltrifluoroborates: Dialkyl Ketone Synthesis
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Visible light photoredox/nickel dual catalysis has been employed in the cross-coupling of acyl chlorides with potassium alkyltrifluoroborates. This protocol, based on single-electron-mediated alkyl transfer, circumvents the restriction of using reactive alkylmetallic nucleophiles in transition-metal-catalyzed acylation and achieves a mild and efficient method for the synthesis of unsymmetrical alkyl ketones. In this approach, a variety of acyl chlorides have been successfully coupled with structurally diverse potassium alkyltrifluoroborates, generating the corresponding ketones with good yields.
- Amani, Javad,Molander, Gary A.
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p. 1856 - 1863
(2017/02/10)
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- Another Role of Copper in the SimmonsSmith Reaction: Copper-catalyzed Nucleophilic Michael-type Cyclopropanation of a,β-Unsaturated Ketones
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Cyclopropanation was performed using the Furukawa procedure with CH2I2/Et2Zn and a,β-unsaturated ketones. The reaction was performed in the presence of a copper salt. The reactivity was highly dependent on the substrate structure, and cyclopropanated products were obtained in better yields than those achieved using the original SimmonsSmith conditions with a ZnCu couple in some cases. Stereospecificity was observed in a certain case; however, the synthesis of an asymmetric version with a chiral ligand was not successful.
- Fujii, Kanami,Misaki, Tomonori,Sugimura, Takashi
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p. 634 - 636
(2014/05/20)
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- Electronic polarizability-based stereochemical model for Sharpless AD reactions
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Softness really is the hard force! Reported here was the critical yet long-overlooked role of electronic polarizability (i.e., softness) effect in controlling absolute stereochemical courses of general asymmetric induction events. Thus, a sensitive dependence of the sense of chiral induction on an alkene substrate's substituent electronic polarizability character was uncovered from a range of structurally highly comparable Sharpless asymmetric dihydroxylation (AD) systems, from which a new polarizability-based stereochemical model of predictive power was suggested.
- Han, Peng,Wang, Ruji,Wang, David Zhigang
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supporting information; experimental part
p. 8873 - 8878
(2011/12/02)
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- Synthesis of Some Substituted Pyrrolidines from Cyclopropyl Carbonyl Compounds
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A series of alkyl and aryl cyclopropyl carbonyl compounds, when refluxed in N-methylformamide in the presence of magnesium chloride, gave variously substituted pyrrolidines.
- Blake, Keith W.,Gillies, Iain,Denney, Ronald C.
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p. 700 - 702
(2007/10/02)
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