Selective Cleavage of Carbamate Protecting Groups from Aziridines with Otera's Catalyst

Abstract

Otera's distannoxane catalyst was found to promote the cleavage of carbamate groups from N-protected aziridines. This method enables the chemoselective cleavage of an aziridinyl N-carbobenzyloxy (Cbz) group in the presence of other N-Cbz groups. The selectivity is due to the longer, weaker N-C bond of aziridinyl carbamates, as inferred through IR and crystallographic analyses.

6th Heron Island Conference on Reactive Intermediates and Unusual Molecules

“…pyridine-palladacycles (G. J. Rowlands et al), [5] benzonitrile oxide cycloadditions (G. P. Savage and C. Francis), [6] adamantanethione reactions (N. Drinnan and C. Wentrup), [7] dyesensitised solar cells (E. Brunet et al), [8] iron complexes (P. Comba et al), [9] boric acid catalysed esterification (T. A. Houston et al), [10] amidinium tetrazolide (A. J. Arduengo et al), [11] use of Otera's catalyst (C. A. Hutton et al), [12] methyltriacetylene cation (J. P. Maier et al), [13] retro-Mannich cascade rearrangement (P. Wipf et al), [14] computations on water dimers (E. Kraka et al), [15] cyclopropane radical cation (W. Zou and D. Cremer), [16] nitrile selenides (T. Pasinszki et al), [17] polarization in a halogen bond (T. Clark et al), [18] triazenes (S. Bräse et al), [19] sydnone photochemistry (C. Wentrup et al), [20] dihydroazulene photoswitches (M. B. Nielsen et al), [21] isocyanide-NHC-platinum(II) complexes (A. S. K. Hashmi et al), [22] benzynes (T. Ikawa et al), [23] gold catalysis (A. S. K. Hashmi et al), [24,25] HERON reaction of dialkoxyamides (S. A. Glover et al), [26] silylated enoldiazoacetates (M. P. Doyle et al), [27] and microflow photochemistry (M. Oelgemöller et al). [28] The lively late-afternoon poster sessions on the patio with a view of the sunset and reef sea life (including whales on occasion) are a recurring and unforgettable part of the Heron Island Conferences (Fig.…”

The Synthesis of (2R)-Aziridine-2-carboxylic Acid Containing Dipeptides

“…36,37 Nonetheless, up to now, literature reports on the preparation of partially or fully deprotected dipeptide derivatives have been rare. To the best of our knowledge, there has been only one report by Korn 36 describing the synthesis of fully deprotected H-Azy-Leu-OH and only a couple of papers describing the synthesis of N-deprotected 21,27,38,39 and C-deprotected dipeptides. 34,36 Most of them suffer from low isolated yields following work-up and chromatography which reflects the inherent instability of these compounds.…”