Totalsynthese von (−)-Mucocin

Bäurle, Stefan; Hoppen, Sabine; Koert, Ulrich

doi:10.1002/(sici)1521-3757(19990503)111:9<1341::aid-ange1341>3.0.co;2-j

Cited by 20 publications

(1 citation statement)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The obtained γ‐ketocarboxylic acid 316 was then transformed over three steps into the corresponding aliphatic aldehyde 317 , which was coupled in a Wittig olefination with the furan derivative 318 as the second building block 109c. Hydrogenation, deprotection, and Swern oxidation yielded another aldehyde 320 , which was coupled with the third building block, the iodide 321 , in a chelation‐controlled Grignard addition 109d. Finally, deprotection and oxidation of the hydroquinone ether 322 gave the hybrid compound 312 .…”

Section: Synthetic Hybrid Moleculesmentioning

confidence: 99%

Natural Product Hybrids as New Leads for Drug Discovery

2003

View full text Add to dashboard Cite

Natural products play an important role in the development of drugs, especially for the treatment of infections and cancer, as well as immunosuppressive compounds. However, the number of natural products is limited, whereas millions of hybrids as combinations of parts of different natural products can be prepared. This new approach seems to be very promising in the development of leads for both medicinal and agrochemical applications, as the biological activity of several new hybrids exceeds that of the parent compounds. The advantage of this concept over a combinatorial chemistry approach is the high diversity and the inherent biological activity of the hybrids.

show abstract

Section: Synthetic Hybrid Moleculesmentioning

confidence: 99%

Natural Product Hybrids as New Leads for Drug Discovery

2003

View full text Add to dashboard Cite

show abstract

Total Syntheses of Squamocin A and Squamocin D, Bi-tetrahydrofuran Acetogenins from Annonaceae

Emde

Koert²

2000

Eur. J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

The total syntheses of the Annonaceous acetogenins squamocin A and squamocin D have been achieved. The synthesis follows a modular strategy, wherein a left‐side chain, the central bis‐THF core and the right‐side chain are assembled together. Key reactions are additions of organomagnesium compounds to bi‐THF aldehydes. At the end of the synthesis the butenolide moiety was introduced. This modular synthetic approach should be useful for the synthesis of other related natural products as well as pharmacologically interesting analogs.

show abstract

Preparation and Applications of Functionalized Organozinc Compounds

et al. 2001

View full text Add to dashboard Cite

Organozinc compounds have been known for more than 150 years. With the exception of zinc enolates (Reformatsky reagents) and iodomethylzinc derivatives (Simmons‐Smith, Furukawa, and Sawada reagents), their synthetic potential has only been recently recognized. This is certainly due to their low reactivity and to the absence of general methods of preparation. Although the carbon‐zinc bond in diethylzinc has a dissociation energy of 34.5 kcal/mol, it has, because of the similar electronegativities of zinc and carbon, a highly covalent character (ca. 85 %), which is comparable to a carbon‐tin bond. The carbon‐zinc bond is therefore inert to moderately polar electrophiles such as aldehydes, ketones, esters, or nitriles. On the other hand, the presence of empty low‐lying p orbitals at the zinc center allows transmetallations with a number of transition metal complexes. This is favored for both kinetic and thermo‐dynamic reasons. The availability of d orbitals at the metal center in these compounds allows for new reaction pathways with electrophilic reagents that were not available for the corresponding zinc reagents. This reactivity has been exploited for the formation of new carbon‐carbon bonds and efficient cross‐coupling reactions between organozinc derivatives and unsaturated organic halides, as Negishi has demonstrated using catalytic amounts of palladium(0) salts. Similar catalytic processes have been reported with copper(I) and titanium(IV) complexes, which can mediate numerous reactions of organozinc reagents with organic electrophiles. The scope and synthetic applications of zinc organometallics were greatly extended when it was found that these species can accommodate a wide range of functional groups. They are ideally suited for the construction of polyfunctional organic molecules without the use of multiple protection and deprotection steps. Although some functionalized organozinc compounds bearing ester groups such had been reported, it was only recently that systematic studies have shown the synthetic potential of these reagents. This chapter describes methods for the preparation of functionalized organozinc halides, diorganozincs, and organozincates and their reactions with electrophilic reagents in the presence of transition metal catalysts, as well as synthetic applications demonstrating their synthetic utility for natural product synthesis. Only the preparation and reactivity of zinc organometallics bearing relatively reactive functional groups are covered. Thus, the chemistry of organozinc compounds bearing an ether, acetal, ketal, trialkylsilyl, or polyfluoroalkyl group is, in general, not covered.

show abstract

Totalsynthese von (−)-Mucocin

Cited by 20 publications

References 34 publications

Natural Product Hybrids as New Leads for Drug Discovery

Natural Product Hybrids as New Leads for Drug Discovery

Total Syntheses of Squamocin A and Squamocin D, Bi-tetrahydrofuran Acetogenins from Annonaceae

Preparation and Applications of Functionalized Organozinc Compounds

Contact Info

Product

Resources

About