Non‐empirical calculations of NMR indirect carbon–carbon coupling constants. Part 6: Propellanes

Abstract

A full set of carbon-carbon coupling constants have been calculated at the SOPPA level in the series of six most representative propellanes. Special attention was focused on spin-spin couplings involving both bridgehead carbons, and these data were rationalized in terms of the multipath coupling mechanism and hybridization effects. Many unknown couplings in the propellane frameworks were predicted with high reliability.

Computational 1H NMR: Part 1. Theoretical background

“…Another representative example deals with the calculation of 1 H-1 H spin-spin coupling constants at the SOPPA level in a series of classically known sterically strained polycycloalkanes shown in Scheme 2, namely, bicyclo[1. (17), and spiropentane (18), which is reported in a series of interrelated publications by Krivdin, [36][37][38][39][40] see Table 2.…”

Non‐empirical calculations of NMR indirect carbon–carbon coupling constants. Part 10—Carbocages

“…A number of saturated carbocycles have been comprehensively investigated in terms of the structural behavior of their carbon-carbon spin-spin coupling constants, J(C,C), as reported in nine previous papers. 1 -9 These include monocycloalkanes, 1,2 spiroalkanes, 3,4 bicycloalkanes, 5 bridged bicycloalkanes, 4,6 bicyclobutane-containing polycycloalkanes, 7 propellanes 4,8 and polyhedranes. 9 The missing link and the last target of our interest is this series are nine caged carbocycles, tetrahedrane (1), prismane (2), homoprismane (3), quadricyclane (4), cubane (5), pentaprismane (6), hexaprismane (7), adamantane (8), and diamantane (9), shown in Fig.…”

Evaluating the accuracy of theoretical one‐bond 13C─13C scalar couplings and their ability to predict structure in a natural product

“…[2,3] The less frequently measured 1 J CC coupling also provides a valuable metric for evaluating structure. [2][3][4][5][6][7][8][9][10][11][12][13][14] In this study, 1 J CC coupling is exclusively emphasized because it directly provides 13 C─ 13 C connectivity in organic structures. This is particularly relevant in hydrogenpoor compounds where structural characterization by more conventional NMR methods is challenging.…”

“…[5] Another important contributor to 1 J CC couplings is the presence of adjacent heteroatoms [9,[32][33][34][35][36][37][38][39][40] where the heteroatom electronegativity and lone electron pair orientation [8,19,20,24,26,28] have been correlated with the magnitude to the 1 J CC coupling. Ring conformation, ring strain, [12,41,42] and percent s-character in a given C─C bond [43][44][45][46][47] have also been experimentally and theoretically shown to influence 1 J CC couplings.…”

“…[13,17,51] Theoretical methods from calculating 1 J CC values have also been developed using various approaches. [2,11,18,24,28,[52][53][54][55][56][57][58] Recent theoretical work often relies upon the secondorder polarization propagator approximation technique [8,11,12,20,22,24,30,31,39,56,59] or density functional theory (DFT) computations [13,14,17,19,23,[26][27][28]33,[36][37][38]41,43,45,54,55,57,60] that employ the EPR-III [61,62] basis set. [3,26,28,30,…”