Pd0-catalyzed coupling cyclization reaction of Aryl or 1-alkenyl halides with 1,2-allenyl ketones: scope and mechanism. An efficient assembly of 2,3,4-, 2,3,5-tri- and 2,3,4,5-tetrasubstituted furans.
Described herein is the Pd(0)-catalyzed coupling cyclization reaction of 1,2-allenyl ketones with organic halides leading efficiently and conveniently to not only 2,3,4- and 2,3,5-trisubstituted furans but also 2,3,4,5-tetrasubstituted furans. Furthermore, this method showed high substituent-loading capability and tolerance of various substituents. The reactions of 1,2-allenyl ketones 1 e, 1 p, 1 q, and deuterated [D]1 c were performed for a mechanistic study, which demonstrated that instead of an enolization pathway, the reaction may proceed via the intermediacy of dienolate palladium and intramolecular nucleophilic attack on the pi-allyl palladium intermediate by the carbonyl oxygen.
Ma
Shengming
S
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China. masm@pub.sioc.ac.cn
Zhang
Junliang
J
Lu
Lianghua
L
D000475:Alkenes / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*
D000475:Alkenes; D005663:Furans; D006846:Hydrocarbons, Halogenated; D007659:Ketones; D010165:Palladium