Abstract The chlorinated natural products, rubrolides B, I, K, L, M and O analogues were synthesized in only five steps employing a robust divergent synthetic strategy. synthesis is performed without using protecting groups starting from key intermediate, which can be commercially available tetronic acid two steps. Selective halogenation vinylogous aldol condensation enable the efficient of hig...

ome of the most useful reactions of carbonyl compounds involve carbonhydrogen bonds adjacent to the carbonyl group. Such reactions, which can be regarded as the backbone of much synthetic organic chemistry, usually result in the replacement of the hydrogen by some other atom or group, as in the I I I I sequence H-C-C=O -+ X-C-C=O. The important examples we I I will consider in this chapter are ...

The antifungal activity of N-chlorotaurine (NCT), a long-lived oxidant produced by stimulated human leucocytes, was investigated. Incubation of Aspergillus spp., Candida spp., Fusarium spp., Penicillium spp. and Alternaria spp. in 1% NCT (55 mM) for 1-4 h produced a log10 reduction in cfu of between 1 and 4. In samples of nasal secretion, killing was significantly hastened (30 min), which may b...

The asymmetric alpha-addition of relatively nonpolar hydrocarbon substrates, such as allyl and aryl groups, to aldehydes and ketones remains a largely unsolved problem in organic synthesis, despite the wide potential utility of direct routes to such products. We reasoned that well-established chiral amine catalysis, which activates aldehydes toward electrophile addition by enamine formation, co...

Gifted with novel chemical features and extraordinary biological activity, sceptrin has remained a prominent unanswered synthetic challenge since its characterization in 1981 by Faulkner and Clardy. A concise and practical solution to the myriad of chemical challenges posed by sceptrin is reported in this Communication. Thus, through a sequence involving rearrangement of an oxaquadricyclane, a ...

Several 2,3-unsaturated carboxylic acids, such as trans-cinnamic acid and its derivatives, were found to be halogenated by chloroperoxidase of Caldariomyces fumago in the presence of hydrogen peroxide and either Cl- or Br-. Cinnamic acid, 4-hydroxycinnamic acid, 4-methoxycinnamic acid, and 3,4-dimethoxycinnamic acid were suitable substrates of chloroperoxidase, and were converted to 2-halo-3-hy...

Halogenated molecules are widely distributed in the biosphere. A variety of halogenated aromatic and aliphatic compounds are man-made and can be harmful to the environment due to their slow rates of biodegradation.1 Halogenated organic molecules can also arise as natural products in which the carbon-halogen bonds are generated enzymatically. To date, more than 4500 halogenated natural products ...

The napyradiomycins are an intriguing family of halogenated natural products with activity against several tumor cell lines as well as some of the worst bacterial strains known to humanity, including methicillin-resistant Staphylococcus aureas and vancomycin-resistant strains of Enterococcus faecium. This communication delineates the first asymmetric total synthesis of (-)-napyradiomycin A1 by ...

A number of organic electrogenerative processes are described and explained by reviewing various aspects of studies associated with them. Electrogenerative hydrogenation, dehydrogenation, halogenation, and oxidation of alcohols are discussed together with possibilities for process improvement. Hydrogenation is used as a model for reviewing studies which correspond to the conventional ones of or...