Silylation of <i>N,O</i>-Diacylhydroxylamines:  NMR Spectra and Structure of the Products Jan Schraml Jaromír Mindl Jana Roithová Vratislav Blechta Jan Sýkora Ludmila Soukupová Jindřich Karban Milena Bártlová Otto Exner 10.1021/om030684u.s001 https://acs.figshare.com/articles/journal_contribution/Silylation_of_i_N_O_i_Diacylhydroxylamines_NMR_Spectra_and_Structure_of_the_Products/3341722 Silylation of <i>N,O</i>-diacylhydroxylamines with <i>N</i>-(<i>tert</i>-butyldimethylsilyl)-<i>N</i>-methyltrifluoroacetamide produces only O-silylated products and no N-silylated derivative. Steric interactions of the substituents on the nitrogen atom with the O−N oxygen atom control the configuration on the CN bond in the product:  a <i>Z </i>isomer is formed almost exclusively from <i>N</i>-benzoylhydroxylamines, and a mixture of <i>E</i> and <i>Z</i> isomers is produced from <i>N</i>-acetyl derivatives. The relative stability of all isomers in various conformations was confirmed by calculations at the B3LYP/6-31G(d,p) level. The <i>tert</i>-butyldimethylsilyl derivatives have been fully characterized by their <sup>1</sup>H, <sup>13</sup>C, <sup>15</sup>N, and <sup>29</sup>Si NMR spectra. 2004-04-26 00:00:00 calculation stability diacylhydroxylamine Z isomer 29 Si NMR spectra configuration acetyl derivatives Products Silylation mixture butyldimethylsilyl derivatives 13 C B 3LYP level Spectra Steric interactions conformation 1 H substituent Z isomers methyltrifluoroacetamide benzoylhydroxylamine Diacylhydroxylamine nitrogen atom tert 15 N bond