Organocatalytic hetero [4+2] cycloaddition reactions of 2-(1-alkynyl)-2-alkene-1-ones: metal-free access to highly substituted 4H-pyrans.
Highly substituted 4H-pyrans can be smoothly synthesized from readily available 2-(1-alkynyl)-2-alkene-1-ones by DBU- or n-Bu(3)P catalyzed hetero-[4+2] cycloaddition reactions, in which 2-(1-alkynyl)-2-alkene-1-ones act as both heterodiene and heterodinenophile.
Yu
Xiuzhao
X
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, PR China.
Cao
Zhongyan
Z
Zhang
Junliang
J
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D011714:Pyrans / Q000737:chemistry*
D000475:Alkenes; D008670:Metals; D011714:Pyrans