Heteronuclear long-range NMR experiments are well established as essential NMR techniques for the structure elucidation of unknown natural products and small molecules. It is generally accepted that the absence of a given (n)JXH correlation in an HMBC or HSQMBC spectrum would automatically place the proton at least four bonds away from the carbon in question. This assumption can, however, be mi...

Fluorous mixture synthesis minimizes the effort to synthesize small-molecule libraries by labelling the molecules rather than the reaction vessels. Reactants are labelled with fluorinated tags and products can later be demixed based on the fluorine content. A limit in the number of available tags can be overcome by using binary encoding so that a total of four tags can label uniquely a library ...

This review covers conformational and configurational assignments in natural product molecules using chiroptical spectroscopy reported over the last 15 years. Special attention is given to vibrational optical activity methods associated with quantum mechanical calculations.

The enantioselective synthesis of the title compound, using Meyers' bicyclic lactam methodology, is described. This compound and a few of its derivatives are useful intermediates in natural product synthesis.

Medium sized carbocycles are particularly difficult to synthesize. Ring closing metathesis reactions (RCM) have recently been applied to construct eight-membered carbocycles, but trisubstituted double bonds in the eight-membered rings are more difficult to produce using RCM reactions. In this review, model examples and our own results are cited and the importance of the preparation of suitably ...

An efficient stereoselective synthetic approach to colomitides, 2,7-dioxabicyclo[3.2.1]octane-type natural products, is reported. Key steps are a stereocontrolled aldol reaction and a gold-catalyzed cycloisomerization. This synthetic strategy has been applied for the first asymmetric total synthesis of the proposed colomitides and their possible diastereomers. Comparison of their 1H and 13C NMR...

The preparation of 4-carbethoxy-5-methyl-2-(phenylsulfonyl)methyloxazole and its use in the elaboration of more complex oxazoles are described. A total synthesis of the unique natural products siphonazoles A and B, illustrates an application of this building block. A discussion of the biological activity of the siphonazoles is also presented.

Cyclodepsipeptide natural products often display intriguing biological activities that along with their complex molecular scaffolds, makes them interesting targets for chemical synthesis. Although cyclodepsipeptides feature highly diverse chemical structures, their synthesis is often associated with similar synthetic challenges such as the establishment of a suitable macrocyclization methodolog...