| 1. |
- Martín-Matute, Belén, et al.
(author)
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Unraveling the Mechanism of the IrIII-Catalyzed Regiospecific Synthesis of α-Chlorocarbonyl Compounds from Allylic Alcohols
- 2020
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In: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 26:65, s. 14978-14986
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Journal article (peer-reviewed)abstract
- We have used experimental studies and DFT calculations to investigate the IrIII-catalyzed isomerization of allylic alcohols into carbonyl compounds, and the regiospecific isomerization–chlorination of allylic alcohols into α-chlorinated carbonyl compounds. The mechanism involves a hydride elimination followed by a migratory insertion step that may take place at Cβ but also at Cα with a small energy-barrier difference of 1.8 kcal mol−1. After a protonation step, calculations show that the final tautomerization can take place both at the Ir center and outside the catalytic cycle. For the isomerization–chlorination reaction, calculations show that the chlorination step takes place outside the cycle with an energy barrier much lower than that for the tautomerization to yield the saturated ketone. All the energies in the proposed mechanism are plausible, and the cycle accounts for the experimental observations.
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| 2. |
- Martinez-Erro, Samuel, et al.
(author)
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Stereospecific Isomerization of Allylic Halides via Ion Pairs with Induced Noncovalent Chirality
- 2020
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In: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 22:11, s. 4123-4128
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Journal article (peer-reviewed)abstract
- A regioselective protocol for the synthesis of substituted allylic chlorides, bromides, and fluorides has been established. Remarkably, the method can be applied to the enantioselective synthesis of challenging chiral allylic chlorides. When the allylic halides are treated with the base triazabicyclodecene as the catalyst, a [1,3]-proton shift takes place, giving the corresponding vinyl halides in excellent yields with excellent Z:E ratios. Furthermore, the [1,3]-proton shift takes place with an outstanding level of chirality transfer from chiral allylic alcohols (<= 98%) to give chiral trifluoromethylated vinyl chlorides.
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