Conjugated diene-assisted allylic C-H bond activation: cationic Rh(I)-catalyzed syntheses of polysubstituted tetrahydropyrroles, tetrahydrofurans, and cyclopentanes from ene-2-dienes.
C-H activation followed by addition to alkenes is challenging in the current C-H activation/functionalization field. We report herein an unprecedented diene-assisted transition-metal-catalyzed activation of allylic C-H bonds and their subsequent insertion into the alkene moieties of conjugated dienes. This novel C-H activation/alkene insertion reaction provides an efficient way to synthesize polysubstituted tetrahydropyrroles, tetrahydrofurans, and cyclopentanes with quaternary carbon centers. Preliminary mechanistic studies using D-labeling experiments have revealed that allylic C-H activation and alkene insertion are reversible steps, whereas the reductive elimination step, which is the final and the rate-determining step of the catalytic cycle, is irreversible.
Li
Qian
Q
Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Yu
Zhi-Xiang
ZX
D000466:Alkadienes / Q000737:chemistry*; D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D003500:Cyclization; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
D000466:Alkadienes; D000498:Allyl Compounds; D002412:Cations; D003517:Cyclopentanes; D005663:Furans; D011758:Pyrroles; C018674:tetrahydrofuran; D012238:Rhodium