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Intramolecular Asymmetric α-Allylation of Aldehydes via SOMO Umpolung
P. V. Pham, K. Ashton, D. W. C. MacMillan*
Princeton University, USA
20 July 2011 (online)
The authors expand SOMO catalysis to the intramolecular α-allylation of aldehydes using a secondary amine catalyst. Under the oxidative reaction conditions [using >2 equiv of ceric ammonium nitrate (CAN)], aldehyde-tethered allylsilanes could be converted into the desired cyclic compounds with good yield and enantioselectivity. Addition of water (2 equiv) could increase chemical yield and diastereoselectivity, however, not the enantioselectivity (see more mechanistic details: Angew. Chem. Int. Ed. 2010, 49, 6106). The presented methodology can be utilized to construct five- and six-membered cyclic compounds with aldehyde and olefin functionalities.