Catalytic dicyanative [4+2] cycloaddition triggered by cyanopalladation of conjugated enynes under aerobic conditions.
A palladium-catalyzed dicyanative [4+2] cycloaddition reaction using dienynes with TMSCN under aerobic conditions is described. This new reaction triggered by the cyanopalladation of terminal alkynes includes regioselective direct cyanation to C-C triple bonds by TMSCN to give pi-allyl Pd intermediates, which promotes 5-exo followed by 6-endo cyclization. This protocol enables (1) the formation of four C-C bonds through one operation, (2) the construction of highly functionalized cyclohexene rings, and (3) the generation of five contiguous stereogenic centers in one operation. The intermolecular cycloaddition reaction between a conjugated enyne and methyl acrylate also proceeded in a regioselective fashion to give multifunctionalized carbocycles.
Graduate School of Pharmaceutical Sciences, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan. arai@p.chiba-u.ac.jp
Shigeru
S
Arai
Yuka
Y
Koike
Hirohiko
H
Hada
Atsushi
A
Nishida
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D013237:Stereoisomerism
D000480:Alkynes; D009570:Nitriles; D010100:Oxygen