... (38) .Huisgen, R. In 1,3-Dipolar Cycloaddition Chemistry; Padwa, A., Ed.; Wiley-Interscience: New York, 1984; Chapter 1. ... 39) Fleming, I. Frontier Orbitals and Organic Chemical Reactions; Wiley-Interscience: New York, 1976. ... 40) Houk, K. N.; Sims, J.; Luskus, L.; Watts, CR J. Am. ...