Premium
Palladium‐Catalyzed Reactions of 3‐Substituted Methylenecyclopropanes
Author(s) -
Shao LiXiong,
Li Jia,
Wang BaoYu,
Shi Min
Publication year - 2010
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001082
Subject(s) - chemistry , acetic acid , isomerization , catalysis , palladium , hydroxymethyl , methylene , medicinal chemistry , substrate (aquarium) , organic chemistry , oceanography , geology
Pd‐catalyzed reactions of 3‐substituted methylenecyclopropanes (MCPs), in which the substituents can be either hydroxymethyl or formyl, have been thoroughly investigated in the presence or absence of an acid source. It was found that the Pd‐catalyzed reactions of methylenecyclopropylcarbinols ( Z )‐ 1 in the presence of acetic acid, acetic acid 2‐methylene‐but‐3‐enyl esters 4 can be formed in moderate yields. It was also found that Pd alone can catalyze the isomerization of methylenecyclopropylcarbinols ( E )‐ 1 in the absence of an acid source to form pent‐4‐enals 3 . The Pd‐catalyzed reactions of methylenecyclopropanecarbaldehydes 5 were also carried out in the presence of acetic acid. It was found that when ( E )‐ 5 was used as the substrate, the isomerized product, penta‐2,4‐dienal 6 , could be obtained in good to high yields, whereas the use of ( Z )‐ 5 gave 2‐(3‐formylpenta‐2,4‐dienylidene)cyclopropanecarbaldehyde 7 in moderate to good yields. Plausible mechanisms for all these transformations have been discussed on the basis of the obtained results and control experiments.