Possible special thermal effects of microwave irradiation are still actively debated (C&EN, Jan. 27, page 26). Paramjit S. Arora and Ross N. Chapman of New York University observed that the Ru-mediated ring-closing metathesis of an oligopeptide was sluggish with oil-bath heating—taking hours. But it proceeded rapidly—that is, in two to five minutes—with microwave heating (Org. Lett. 2006, DOI:10.1021/ol062443z). Could cis-trans amide flip be directly stimulated by microwaves?
Douglass F. TaberIt'll be interesting to see if Kappe decides to respond to this.