The Mechanism of the Rappe Rearrangement – a stereochemical investigation using Density Functional Theory.
DOI: 10.14469/hpc/11172 Metadata
Created: 2022-09-19 11:00
Last modified: 2025-06-12 06:33
License: Creative Commons: Public Domain Dedication 1.0
Funding: (none given)
Co-author: Toby Sommer
Description
Since it was first described in the 1950s, there has been no explanation of the extraordinarily high selectivity for the formation of the thermodynamically less stable cis-2-alkenoic acids from treatment of α,α'-dibromoketones with aqueous base. Very early on, it was suggested that such specificity must arise via “concerted processes” but without elaboration. Provided here is a detailed mechanistic description of the reaction based on computational insight, identifying a stereospecific first step for the ring closure to a 3-ring cyclopropanone which follows Woodward-Hoffmann rules for a two-electron allylic cation, accompanied by departure of a bromine atom in an SN2-like process. The stereochemistry established in this step persists in the second step, which involves ring-opening of the 3-ring to give a cis-2-alkenoic acid. Other mechanistic pathways have higher energies. With this new understanding, further synthetic applications of the Rappe Rearrangement are suggested.
Members
| DOI | Description |
|---|---|
| 10.14469/hpc/11036 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS1 pathway forming cyclopropanone. |
| 10.14469/hpc/11044 | The Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS3 and TS4 pathways |
| 10.14469/hpc/11174 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. Mechanistic scheme, IRC pathways and animations |
| 10.14469/hpc/11178 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS5 pathways |
| 10.14469/hpc/11051 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS2 pathway |
| 10.14469/hpc/11224 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS8 pathways |
| 10.14469/hpc/11181 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. TS6/7 homologue. |
| 10.14469/hpc/15063 | Rappe Rearrangement. The origin of cis-stereoselectivity in the conversion of 2,3-dibromo-2-methyl-cyclopropan-1-one to (Z)-but-2-enoic acid. Products and Thermochemistry of overall reaction |
Associated DOIs
| Current dataset ... | DOI | Description |
|---|---|---|
| References | 10.1021/acs.joc.5c00726 | Article: The Mechanism of the Rappe Rearrangement a stereochemical investigation using Density Functional Theory |
| isReferencedBy | 10.1021/acs.joc.5c00726 | Article: The Mechanism of the Rappe Rearrangement a stereochemical investigation using Density Functional Theory |
| References | 10.14469/hpc/11039 | Rappe Rearrangement. FAIR Data Table 1 for TS1 |
| References | 10.14469/hpc/11227 | Rappe Rearrangement. FAIR Data Table 2 for TS2 |
| References | 10.14469/hpc/11228 | Rappe Rearrangement. FAIR Data Table 3 for TS3 and TS4 |
| References | 10.14469/hpc/11230 | Rappe Rearrangement. FAIR Data Table 4 for TS5 |
| References | 10.14469/hpc/11231 | Rappe Rearrangement. FAIR Data Table 5 for TS6 and TS7 |