Asymmetric Catalysis of the Transannular Diels-Alder Reaction
Emily P. Balskus and
Eric N. Jacobsen*
Transannular chemical reactions are unparalleled in their ability
to generate high degrees of stereochemical and architectural
complexity in a single transformation. However, the successful
application of this approach in synthesis depends on the ability
to predict and control the outcome of the transannular reaction.
Use of a chiral catalyst in this context represents an attractive,
yet unused, strategy. This report describes a catalytic, asymmetric
transannnular Diels-Alder (TADA) reaction that affords polycyclic
products in high enantiomeric excess. This catalyst system can
also alter the inherent diastereoselectivity of cyclizations
with substrates containing chiral centers. Additionally, the
catalytic enantioselective TADA has been used as the key step
in a total synthesis of the sesquiterpene 11,12-diacetoxydrimane;
this route may provide a general approach to the polycyclic
carbon framework shared by many terpene natural products.
* To whom correspondence should be addressed. E-mail: jacobsen{at}chemistry.harvard.edu
