- β-Diazocarbonyl Compounds: Synthesis and their Rh(II)-Catalyzed 1,3 C?H Insertions
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Herein, we describe the first electrophilic diazomethylation of ketone silyl enol ethers with diazomethyl-substituted hypervalent iodine reagents that gives access to unusual β-diazocarbonyl compounds. The potential of this unexplored class of diazo compounds for the development of new reactions was demonstrated by the discovery of a rare Rh-catalyzed intramolecular 1,3 C?H carbene insertion that led to complex cyclopropanes with excellent stereocontrol.
- Jiang, Liyin,Wang, Zhaofeng,Armstrong, Melanie,Suero, Marcos G.
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supporting information
p. 6177 - 6184
(2021/02/01)
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- Stereoselective Synthesis of Trisubstituted Vinylboronates from Ketone Enolates Triggered by 1,3-Metalate Rearrangement of Lithium Enolates
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An unprecedented stereoselective synthesis of trisubstituted vinylboronates is reported to proceed by direct borylation of lithium ketone enolates under transition-metal-free conditions. The stereospecific C?O borylation of lithium enolates was triggered by a carbonyl-induced 1,3-metalate rearrangement via a C-bound boron enolate. DFT calculations and control experiments revealed that the stereoselectivity is controlled by sterics. A variety of stereospecific trisubstituted vinylboronates, together with several tetrasubstituted vinylboronates, were conveniently synthesized with the newly developed methodology. Based on the transformation of stereospecific vinylboronate, a single isomer of Dienestrol was efficiently obtained.
- Hu, Yue,Sun, Wei,Zhang, Tao,Xu, Nuo,Xu, Jianeng,Lan, Yu,Liu, Chao
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supporting information
p. 15813 - 15818
(2019/10/28)
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- Investigations into the regioselective C-deuteration of acyclic and exocyclic enolates
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Results are reported on the regioselective C-deuteration of a series of related acyclic and exocyclic enolates derived from substituted aryl ketones. We comment on factors, such as the presence of additives and the structural nature of the enolate, that influence the observed C-deuteration and discuss the role of the deuterium donor. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Eames, Jason,Coumbarides, Gregory S.,Suggate, Michael J.,Weerasooriya, Neluka
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p. 634 - 641
(2007/10/03)
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- Generation, Alkylation, and Silylation of Directed Enolates Formed by Reaction of Ketenes and Organolithium Reagents
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Symmetrical ketenes R2C=C=O R2=t-Bu2(1), Et2(2),(CH2)4(3),(CH2)5(4) were reacted with organolithium reagents R'Li to give directed enolates R2C=C(OLi)R' which were alkylated with MeI or silylated with Me3SiCl.The silylation results for 2-4 were compared to those for reaction of ketones R2CHCO-n-Bu (16-18) with Me3SiCl and either i-Pr2NLi, KH, or Et3N.These latter conditions usually favored different regioisomers from the ketene route.Reaction of 1 with t-BuLi gave the previously inaccessible enolate t-Bu2C=C(OLi)-t-Bu (25), which on reaction with MeI gave a mixtureof the O-methylation product 27 along with some C-methylation product and with Me3SiCl gave the silyl enol ether 26.The vinyl ethers 26 and 27 are among the first substituted tri-tert-butylethylenes which have been reported.
- Baigrie, Lynn M.,Lenoir, Dieter,Seikaly, Hani R.,Tidwell, Thomas T.
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p. 2105 - 2109
(2007/10/02)
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