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Photochemische Reaktionen 42. Mitteilung [1]. Photoisomerisierung von α, β‐Epoxyketonen II Der sterische Verlauf der Umlagerung von 3‐Oxo‐4, 5‐oxido‐Steroiden
Author(s) -
Wehrli H.,
Lehmann C.,
Iizuka T.,
Schaffner K.,
Jeger O.
Publication year - 1967
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19670500827
Subject(s) - chemistry , alicyclic compound , epimer , stereochemistry , alkyl , carbon atom , medicinal chemistry , organic chemistry
The photorearrangement previously described [3] of saturated and Δ 1 ‐unsaturated 3‐oxo‐4,5‐epoxy‐10β‐steroids to 3,5‐dioxo‐10(5 →4)‐ abeo compounds proceeds most likely via a radical 1,2‐alkyl shift (Chart 1). The similar rearrangements of the related 10α‐epoxyketone 10 and the 4‐methyl‐epoxyketones 13 , 15 , 16 , 20 and 21 to the corresponding 3,5‐diketones occurred without epimerization at the migrating carbon atom (C‐10) and the site of substitution (C‐4) (Chart 3). The stereochemical control of the rearrangement is in agreement with the earlier proposed mechanism of a concerted alkyl radical shift in these alicyclic systems.