title: Rh(I)-catalyzed formal [6 + 2] cycloaddition of 4-allenals with alkynes or alkenes in a tether.
abstract: Rh(I)-catalyzed formal [6 + 2] cycloaddition of allenal 6 having an alkyne or alkene in a tether proceeded smoothly, giving 5-8- and 6-8-fused bicyclic ketone derivatives 7 in good to excellent yields. It was also found that cyclization of enantiomerically enriched (S)-6a (94% ee) gave cyclic ketone derivative (S)-7a in high yield with reasonable chirality transfer (86% ee). This result indicates that this cyclization proceeds through stereoselective formation of rhodacycle H' followed by insertion of a multiple bond.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan. oonishi@pharm.hokudai.ac.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Oonishi
authors.forename: Akihito
authors.initials: A
authors.lastname: Hosotani
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sato
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000480:Alkynes; D012238:Rhodium