- Stereodivergent Olefination of Enantioenriched Boronic Esters
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A stereodivergent coupling reaction between vinyl halides and boronic esters is described. This coupling process proceeds without a transition-metal catalyst, instead proceeding by electrophilic selenation or iodination of a vinyl boronate complex followed by stereospecific syn or anti elimination. Chiral, nonracemic boronic esters could be coupled with complete enantiospecificity. The process enables the highly stereoselective synthesis of either the E or Z alkene from a single isomer of a vinyl coupling partner.
- Armstrong, Roly J.,García-Ruiz, Cristina,Myers, Eddie L.,Aggarwal, Varinder K.
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supporting information
p. 786 - 790
(2017/01/14)
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- Synthesis of cyclic peroxides by chemo- and regioselective peroxidation of dienes with Co(II)/O2/Et3SiH
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(Chemical Equation Presented). In the competitive peroxidation of mixtures of two alkenes with Co(II)/O2/Et3SiH, it was found that the relative reactivities of the alkene substrates are influenced by three major factors:. (1) relative stability of the intermediate carbon-centered radical formed by the reaction of the alkene with HCo(III) complex, (2) steric effects around the C=C double bond, and (3) electronic factors associated with the C=C double bond. Consistent with results from simple alkenes, the chemo-and regioselective peroxidation of dienes was also realized. Depending on the diene structure, the product included not only the expected acyclic unsaturated triethylsilyl peroxides but also 1,2-dioxolane and 1,2-dioxane derivatives via intramolecular cyclization of the unsaturated peroxy radical intermediates.
- Tokuyasu, Takahiro,Kunikawa, Shigeki,McCullough, Kevin J.,Masuyama, Araki,Nojima, Masatomo
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p. 251 - 260
(2007/10/03)
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