Sequence of δ-carbon signals in 2-substituted adamantanes determined by two-dimensional correlated NMR spectroscopy

✍ Scribed by Helmut Duddeck; Manfred Kaiser; Doris Rosenbaum

• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 228 KB
• Volume: 27
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85508-2

✦ Synopsis

The b-carbon resonances of 23 Z-substituted adamantanes were assigned unequivocally by two-dimensional (ZD) correlated NMR spectroscopy. It is shown that in contrast to all previously published instances the 6 carbon signal sequence is reversed for 10 other substituents. 2 1 -_x' -y* 'Y3 Since the advent of one-and two-dimensional double-quantum 13c NMR spectroscopy (INADEQUATE)' new interest arose in the signal assignments of substituted adamantanes 3-6 andg diamantanes4' 7. Very recently, our previous assignments in some Z-substituted adamantanes were confirmed by ZD-INADEQUATE experiments5 for X=Br and C6H5. Thus, one may be led to the conclusion that, apparently in general, the C7 atom (b-anti) is more shielded that C5 (Gsyn). However, our latest highfield 'H and l3 C NMR investigation of these compounds showed that this is not at all correct. Therefore, we want to present preliminarily our results concerning the sequence of the &carbon signals. Our unequivocal assignment is based on a combination of heteroand homonuclear correlated '2D NMR spectroscopy". This is demonstrated for X q C(CH ) OH in Figs. 1 and 2: the H4/H9 and H'/H"signals can be identified by the heteronuclear ( 31 213 H-C) correlated 2D NMR spectrum

This is also valid for isomeric diadamantylphosphinic acid chlorides: H. Duddeck,