Construction of Monocyclic Eight-Membered Rings: Intermolecular Rhodium(I)-Catalyzed [6+2] Cycloaddition of 4-Allenals with Alkynes
作者:Yoshihiro Oonishi、Akihito Hosotani、Yoshihiro Sato
DOI:10.1002/anie.201206508
日期:2012.11.12
Rounding up: A RhI‐catalyzed intermolecular cycloaddition of 4‐allenals with alkynes has been developed that provides various monocyclic eight‐membered rings in good to high yields in a stereoselective manner (see scheme). In addition, the chirality of the starting allene is transferred in this reaction, thereby giving optically active monocyclic eight‐membered ring compounds.
Rhodium(I)-Catalyzed Cyclization of Allenynes with a Carbonyl Group through Unusual Insertion of a CO Bond into a Rhodacycle Intermediate
作者:Yoshihiro Oonishi、Takayuki Yokoe、Akihito Hosotani、Yoshihiro Sato
DOI:10.1002/anie.201308824
日期:2014.1.20
Rhodium(I)‐catalyzed cyclization of allenynes with a tethered carbonyl group was investigated. An unusual insertion of a CO bond into the C(sp2)–rhodium bond of a rhodacycle intermediate occurs via a highly strained transition state. Direct reductive eliminationfrom the obtained rhodacyle intermediate proceeds to give a tricyclic product containing an 8‐oxabicyclo[3.2.1]octane skeleton, while β‐hydride