Cycloaddition of alkynyl ketones with N-tosylimines catalyzed by Bu3P and DMAP: synthesis of highly functionalized pyrrolidines and azetidines.
Cycloadditions of alkynyl ketones with N-tosylimines catalyzed by Lewis bases to synthesize azetidines and pyrrolidines were systematically described. In the reaction of alkynyl ketones with N-tosylimines catalyzed by Bu3P at room temperature in toluene, highly functionalized pyrrolidines were formed in good to excellent yields. When DMAP was used in place of Bu3P as catalyst to facilitate the cycloaddition, completely substituted azetidines were produced in moderate to good yields in CH2Cl2. Both cyclization reactions proceeded smoothly with complete stereoselectivity. The scope and limitations of these cycloaddition reactions were also investigated.
Department of Chemistry, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Ling-Guo
LG
Meng
Peijie
P
Cai
Qingxiang
Q
Guo
Song
S
Xue
D001384:Azetidines / Q000138:chemical synthesis*; D002384:Catalysis; D003500:Cyclization; D007097:Imines / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D011759:Pyrrolidines / Q000138:chemical synthesis*; D014105:Tosyl Compounds / Q000737:chemistry
D001384:Azetidines; D007097:Imines; D007659:Ketones; D011759:Pyrrolidines; D014105:Tosyl Compounds