## Abstract Hexahydrocolupulone (4) and (β)Rβtetrahydrohumulone (5) are regiospecifically oxidized by singlet oxygen at ring carbon atom 4. The reaction proceeds by addition of singlet oxygen to the Ξ΄4β5 enolic function with formation of a perepoxide intermediate. Rearrangement affords the 4βhydrop
Oxidation of Cyclopropylidenes with Ozone and (Singlet) Oxygen
β Scribed by A. Hofland; Th. J. De Boer; H. Steinberg
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2010
- Weight
- 46 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0037-9646
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π SIMILAR VOLUMES
main product. \r.hich undergoes stereoselective Diels-Alder addition with 1 ,3-dienesll1. Elucidation of the mechanism of this reaction required X-ray determination of the configuration and conformation of ( I ).
is removed with trifluoroacetic acid (TFA/CH2C12, 1 : 1 ; yield 5.9 g = 70 % as TFA derivative). In analogy to the above two peptide linkages the protected pentapeptide Boc-L-Tyr(Bz1)-Gly-Gly-L-Phe-L-Met-OMe (1.2 g, 77 % yield) was obtained from Boc-L-Tyr(Bz1)-Gly-Gly-O H (1 g, 2 mmol) and H -L -P
chain reaction already accepted in the case of other bicy-cl~[l.l.O]butanes[~~. Why does the phenylthio radical attack benzvalene (1) at the double bond but homobenzvalene (8) at the bicy-clot1 .I .O]butane system? Since thio radicals have electrophilic characterf7I, the interaction with the HOMO o