... e), are probably incapable of hyperconjugation on stereo- chemical grounds, spectroscopically resemble XIX. ... Burgsthaler, J. Am. Chem. Soc., 75, 384 (1953). ... (33) LF Fieser, Experiments in Organic Chemistry, 2nd ed., D. C. Heath and Company, New York, N: Y., 1941, p. 399. ...
[Stoermer, Martin J.; Butler, Douglas N.; Warrener, Ronald N.; Weerasuria; Fairlie, David P. Chemistry - A European Journal, 2003 , vol. 9, # 9 p. 2068 - 2071]