Intramolecular Diels-Alder Reactions of Decatrienoates: Remote Stereocontrol and Conformational Activation(1).
The intramolecular Diels-Alder (IMDA) reactions of C(8)-substituted decatrienoates have been studied. The stereospecific formation of 11 via an endo-boat-9 transition state attests to the powerful directing influence of a C(8) substituent in the IMDA of decatrienoate. In addition, the contrasting observations that stereospecific 9 --> 11 occurs at room temperature while the nor-tert-butyl substrate (4a) requires 125 degrees C/5 h reaction conditions and produces a 60:40 mixture of diastereomers provide clear evidence that a bulky C(8) substituent is a powerful conformational activator of the IMDA.
Kim
P
Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616-5295.
Nantz
MH
Kurth
MJ
Olmstead
MM