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Photochemical Reactions. Part 67. photochemistry of saturated aliphatic and cyclic β‐keto sulfoxides (C α S)‐ and α‐cleavage – A new case of photostereomutation
Author(s) -
Ganter C.,
Moser J.F.
Publication year - 1971
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.19710540761
Subject(s) - chemistry , sulfoxide , bicyclic molecule , photodissociation , cleavage (geology) , photochemistry , irradiation , medicinal chemistry , excited state , bond cleavage , organic chemistry , catalysis , physics , geotechnical engineering , fracture (geology) , nuclear physics , engineering
The photochemical behaviour of saturated aliphatic ( 2, 4 , and 5 ) and bicyclic ( 18 and 19 ) β‐keto sulfoxides has been studied. Photostereomutation of the sulfoxide group was observed on irradiation of 4a, 4b, 18 , and 19 . Most likely an internal energy transfer from the excited carbonyl to the sulfoxide group is operating on direct irradiation of such compounds. Prolonged photolysis of an aliphatic β‐keto sulfoxide, which is nonalkylated a t the α‐carbon ( 2 ), yielded a product due to preferential (C α ‐S)‐cleavage ( 24 ). Mono‐ ( 4 ) and dialkylated‐ ( 5 , 6 , and 8 )analogues primarily afforded products due to α‐cleavage ( 26–31 and 32 ). The carboxylic acid S‐methylesters ( 26–31 ) were exclusively formed by an intermolecular path. Prolonged irradiation of the bicyclic β‐keto sulfoxides 18 and 19 favored the formation of a desulfurized compound 34 due to initial ( C α ‐S )‐cleavage.