Pure Appl. Chem., 2008, Vol. 80, No. 5, pp. 979-991
doi:10.1351/pac200880050979
Palladium-catalyzed selective activation of allyl alcohols as allyl cations, allyl anions, and zwitterionic trimethylenemethanes*
Yoshinao Tamaru and Masanari Kimura
Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, 1-14 Bunkyo, Nagasaki 852-8521, Japan
Abstract:
Pd-Et3B catalytic system promotes the generation of allyl cations, allyl anions, and zwitterionic trimethylenemethane species from the corresponding allylic alcohols. Allyl cations react with a wide variety of nucleophiles, e.g., amines, active methylene compounds, 1,3,5-trihydroxybenzene, indoles, aldehydes (at the α-position). The reaction is extended to dehydrative Grob fragmentation of 1,3-diols. Allyl anions react with aldimines to give homoallyl amines. Zwitterionic trimethylenemethane, generated from 2-methylene-1,3-propanediol, reacts with aldehydes and aldimines to provide 3-methylenecyclopentanols and 3-methylenepyrrolidines, respectively. Vinyl epoxide can be utilized as a synthetic equivalent of 3-butenyl 2-anion-1-cation.
Keywords: allyl alcohols; allyl anions; allyl cations; catalysis; palladium; triethylborane; trimethylenemethane; umpolung.
*Paper based on a presentation at the 14th International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-14), 2-6 August 2007, Nara, Japan. Other presentations are published in this issue, pp. 807-1194.
Full text is not freely available, please see subscription information for options to access it.
| References (40)