9144 J. Org. Chem., Vol. 63, No. 24, 1998
Additions and Corrections
) 0.2), which was identical, in all respects, to an authentic sample obtained from the Aldrich Chemical Co.
Acknowledgment. We thank the Institute of Advanced Studies for financial support including the provision of a postgraduate scholarship to S.G.S. and a postdoctoral fellowship to B.L.F.
Supporting Information Available: Selected NMR spectra for compounds 12, 13, 15, 20, 26, 28, and 29 (8 pages). This material is contained in libraries on microfiche, immediately follows this article in the microfilm version of the journal, and can be ordered from the ACS; see any current masthead page for ordering information. JO9808526
Additions and Corrections Vol. 61, 1996
Vol. 62, 1997
James S. Nowick,* Darren, L. Holmes, Glenn Noronha, Eric M. Smith, Tram M. Nguyen, Sheng-Lin Huang, and Edward H. Wang. Synthesis of Peptide Isocyanates and Isothiocyanates.
Bosco D’Sa, Dale McLeod, and John G. Verkade*. Nonionic Superbase-Catalyzed Silylation of Alcohols.
Page 3929. Efficient stirring is essential to prevent epimerization in the synthesis of peptide isocyanates described in this paper. When L,L-phenylalanylleucine methyl ester hydrochloride (L,L-1a) was converted to the corresponding isocyanate (L,L-2a) with magnetic stirring or slow (e300 rpm) mechanical stirring, 1.3-8.8% of the epimeric isocyanate (D,L-2a) formed (Table 2). When the reaction mixture was mechanically stirred rapidly (>400 rpm), little epimerization (
