Catalytic Asymmetric [4+2]-Cycloaddition of Dienes with Aldehydes
journal contributionposted on 25.09.2017, 14:21 by Luping Liu, Hyejin Kim, Youwei Xie, Christophe Farès, Philip S. J. Kaib, Richard Goddard, Benjamin List
Despite its significant potential, a general catalytic asymmetric [4+2]-cycloaddition of simple and electronically unbiased dienes with any type of aldehyde has long been unknown. Previously developed methodologies invariably require activated, electronically engineered substrates. We now provide a general solution to this problem. We show that highly acidic and confined imidodiphosphorimidates (IDPis) are extremely effective Brønsted acid catalysts of the hetero-Diels–Alder reaction of a wide variety of aldehydes and dienes to give enantiomerically enriched dihydropyrans. Excellent stereoselectivity is generally observed and a variety of scents and natural products can be easily accessed.