Synthetic studies on the avermectins: substituent effects on intramolecular Diels-Alder reactions of N-furfurylacrylamides and further reactions of the cycloadducts
ME Jung, LJ Street
文献索引：Jung, Michael E.; Street, Leslie J. Journal of the American Chemical Society, 1984 , vol. 106, # 26 p. 8327 - 8329
__ probably a case of the Thorpe-Ingold effect. I3 Force-field calculation^'^ indicate that the two diastereomers differ in energy by-1.2 kcal/mol, favoring the endo isomer. Thus the diastereoselectivity must be due to a kinetic preference for the endo as well as a thermodynamic one. I5 Hydroxylation of 9b under the usual conditions proceeded in c1 k,/6 8% R-C1 62% conditions (100 OC for-5 min or 25 OC for 12 h). In this case the product 9f ...
