On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds
The scope and limitations are described of reacting unsaturated tosylhydrazones with O3 followed by Et3N for the generation of 1,4- and 1,5-diazocarbonyl systems. Tosylhydrazones, from tosylhydrazide condensation with readily available δ- and ε-unsaturated α-ketoesters, led in the former case to a 2...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
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Royal Society of Chemistry
2018
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| _version_ | 1797072122504282112 |
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| author | Fegheh-Hassanpour, Y Ebrahim, F Arif, T Sintim, H Claridge, T Amin, N Hodgson, D |
| author_facet | Fegheh-Hassanpour, Y Ebrahim, F Arif, T Sintim, H Claridge, T Amin, N Hodgson, D |
| author_sort | Fegheh-Hassanpour, Y |
| collection | OXFORD |
| description | The scope and limitations are described of reacting unsaturated tosylhydrazones with O3 followed by Et3N for the generation of 1,4- and 1,5-diazocarbonyl systems. Tosylhydrazones, from tosylhydrazide condensation with readily available δ- and ε-unsaturated α-ketoesters, led in the former case to a 2-pyrazoline whereas the latter cases led to α-diazo-ε-ketoesters, although a terminal alkene produced a tetrahydropyridazinol. Using the ozonolysis–Et3N strategy, tosylhydrazones from cyclic enones give 2,5- and 2,6-diazoketones with aldehyde or ester functionality at the 1-position; the α-diazoaldehydes prefer the s-trans conformation, with a rotation barrier of 74 kJ mol−1 at 25 °C determined by NMR. This one-pot ozonolysis/Bamford–Stevens chemistry demonstrates both the tolerance of tosylhydrazones to ozone, and the subsequently added amine playing a dual role to directly transform the intermediate tosylhydrazone ozonides into products containing reactive diazo and ketone functionalities; such adducts are of particular value as precursors to cyclic carbonyl ylides for 1,3-dipolar cycloadditions. |
| first_indexed | 2024-03-06T23:03:06Z |
| format | Journal article |
| id | oxford-uuid:62dd4d0d-c90f-4dba-bbe2-b433503a9846 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T23:03:06Z |
| publishDate | 2018 |
| publisher | Royal Society of Chemistry |
| record_format | dspace |
| spelling | oxford-uuid:62dd4d0d-c90f-4dba-bbe2-b433503a98462022-03-26T18:09:00ZOn the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compoundsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:62dd4d0d-c90f-4dba-bbe2-b433503a9846Symplectic Elements at OxfordRoyal Society of Chemistry2018Fegheh-Hassanpour, YEbrahim, FArif, TSintim, HClaridge, TAmin, NHodgson, DThe scope and limitations are described of reacting unsaturated tosylhydrazones with O3 followed by Et3N for the generation of 1,4- and 1,5-diazocarbonyl systems. Tosylhydrazones, from tosylhydrazide condensation with readily available δ- and ε-unsaturated α-ketoesters, led in the former case to a 2-pyrazoline whereas the latter cases led to α-diazo-ε-ketoesters, although a terminal alkene produced a tetrahydropyridazinol. Using the ozonolysis–Et3N strategy, tosylhydrazones from cyclic enones give 2,5- and 2,6-diazoketones with aldehyde or ester functionality at the 1-position; the α-diazoaldehydes prefer the s-trans conformation, with a rotation barrier of 74 kJ mol−1 at 25 °C determined by NMR. This one-pot ozonolysis/Bamford–Stevens chemistry demonstrates both the tolerance of tosylhydrazones to ozone, and the subsequently added amine playing a dual role to directly transform the intermediate tosylhydrazone ozonides into products containing reactive diazo and ketone functionalities; such adducts are of particular value as precursors to cyclic carbonyl ylides for 1,3-dipolar cycloadditions. |
| spellingShingle | Fegheh-Hassanpour, Y Ebrahim, F Arif, T Sintim, H Claridge, T Amin, N Hodgson, D On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title | On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title_full | On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title_fullStr | On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title_full_unstemmed | On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title_short | On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
| title_sort | on the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds |
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