Survey of NMR experiments for the determination of nJ(C,H) heteronuclear coupling constants in small molecules

A survey of heteronuclear correlation experiments for the measurement of heteronuclear coupling constants is presented. The purpose of this survey is to evaluate several recent experiments for measuring (n)J(C,H) (n = 2,3) couplings in one comprehensive review. Ten experiments are presented and evaluated relative to one another in terms of experimental usability, ease of data interpretation and number of usable correlations. The experiments compared in this survey are the sensitivity-improved hetero-(omega (1))-half-filtered TOCSY (HETLOC), carbon-sorted HETLOC (HSQC-HECADE), coupled/decoupled HSQC-TOCSY, GSQMBC, HSQMBC, G-BIRDR,X-HSQMBC, J-resolved HMBC-2, I-IMPEACH-MBC and methods for extracting heteronuclear coupling constants from gradient-selected variants of the magnitude-mode and phase-sensitive HMBC. The plant alkaloid strychnine was used as a model compound for this study. Copyright (C) 2001 John Wiley & Sons, Ltd.