Reaction of bis-lactone in rigid polycycles with alkyl lithiums. Synthesis of novel oxa-cace compounds

Reaction of bis-lactone embodied in the rigid tircyclo [5.2.1.02,6] decane 5 with MeLi and t-BuLi produced the novel oxa-cage compounds 9 and 11 instead of the expected ketones 6

Synthesis of methyl-6-methyl tricyclo[5.2.1.0<SUP>2,6</SUP>]decan-9-one-2-carboxylate: potential intermediate to isocomene and cuprenolide

A facile synthesis of methyl-6-methyl tricyclo [5.2.1.02,6]decan-9-one-2-carboxylate 7, a potential intermediate to isocomene 6 and cuprenolide 8 is described

Aortic aneurysm and non-Hodgkin’s lymphoma in Marfan syndrome

The combination of Marfan syndrome with lymphoma is extremely rare. This report describes a case of Marfan syndrome who presented with chest discomfort and was diagnosed to have an aortic aneurysm and an additional incidental mediastinal mass that on further investigation turned out to be a diffuse large B cell lymphoma. We have suggested a hypothesis which can explain the occurrence of lymphoma in Marfan syndrome

The Development of New Classes of Enantioselective Hydrogen Bond Donor Catalysts for Organic Synthesis Based upon Werner Complexes

In this dissertation, the development of highly effective, chiral monofunctional and bifunctional hydrogen bond donor catalysts based on cobalt(III) Werner complexes and their applications in enantioselective catalysis have been described. Furthermore, a protocol was developed to extend this chemistry into the fluorous media. Section 1 provides an overview of the hydrogen bond mediated organocatalysis and the scope of Werner complexes as hydrogen bond donors. Section 2 describes the fundamental stereochemical features of the trication [Co(en)3]3+ (en = ethylenediamine). Interactions between the trication, counter anions, and solvates are analyzed and a systematic nomenclature is developed. Section 3 provides highly diastereoselective syntheses of variety of diastereopure salts Λ- and Δ-[Co((S,S)-NHv2CHArCHArNHv2)v3]^3+ 2X–X'– (Ar = Cv6Hv5, vCv6Hv4n-Bu, 4- Cv6Hv4Cl, 4-Cv6Hv4CFv3, 4-Cv6Hv4OCHv3, ɑ-naphthyl, ß-naphthyl, 2-Cv6Hv4OBn; X/X' = Cl/BArvf (BArvf = B(3,5-Cv6Hv3(CFv3)v2)v4), PFv6/BArf, BF4/BArf, PhBF3/BArf, Cl/BArf20 (BArvf20 = B(Cv6F5)4), BArf/BArf, BArf20/BArvf20, BFv4/BFv4, PFv6/PFv6) and probes their properties. Sections 4 and 5 provide detail applications of the lipophilic salts of Λ- or Δ- [Co((S,S)-dpen)v3]^3+ ((S,S)-dpen = (S,S)-1,2-diphenylethylenediamine) in enantioselective addition reactions. Under optimized conditions, Λ-[Co((S,S)-dpen)v3]^3+ 3BFv4– catalyzes the Michael addition of dialkyl malonate to nitroalkenes in the presence of Et3N, affording adducts in up to 98% yields and 96% ee. Interestingly, Δ-[Co((S,S)- dpen)v3]^3+ 2Cl–BArvf20– is superior for the additions of cyclic ß-ketoesters to azodicarboylate diesters (up to 99% yields and >99% ee). Section 6 describes efficient syntheses of tris(hydrochloric acid) salts of chiral triamines Hv2NCH((CHv2)nNMe2)CHv2NHv2 (n = 1-4) from commercial starting materials in overall yields of 38-18%. Section 7 highlights syntheses of bifunctional catalysts and their applications in additions of dialkyl malonates to nitroalkenes. Racemic [Co(en)v2Ov2CO]^+ Cl^– and enantiopure (S)-[Hv3NCH((CH2)nNHMe2)CHv2NHv3]^3+ 3Cl^– (n = 1-4) are combined (water/ charcoal/100 °C) to give [Co(en)v2((S)-Hv2NCH((CHv2)vnNMev2H)CHv2NHv2)]4^+ 4Cl^–. The cobalt diastereomers (Δ/Δ)are separated via chiral Sephadex columns. Reactions with NaOH and Na^+ BArvf^– give the catalysts Λ- or Δ-[Co(en)v2((S)-Hv2NCH- ((CHv2)nNMev2)CHv2NHv2)]^3+ 3BArvf^–. Under optimized condition, Λ-[Co(en)v2((S)- Hv2NCH((CHv2)v3NMev2)CHv2NHv2)]^3+ 3BArvf^– gives addition products up to 98% yield and 99% ee. Section 8 describes an optimized procedure for the synthesis of highly fluorous Na^+ B(3,5-Cv6Hv3((CFv2)5CFv3)v2)v4– and its application in transporting polycations into fluorous media

A new stereoselective route to the carbocyclic nucleoside cyclobut-A

A new synthesis of cyclobut-A, a carbocyclic nucleoside analogue of oxetanocin is described. The key step involves a stereoselective intramolecular [2+2] photocycloaddition to provide a trisubstituted cyclobutane derivative with the desired stereochemistry. The nucleoside linkage was established through nucleophilic displacement of an acetate group by adenine

Factors influencing ring closure through olefin metathesis- a perspective

Success of ring closure reactions of substrates having two terminal alkenes through olefin metathesis depends on a number of factors such as catalysts, nature and size of the rings to be formed and the substituents/functional groups present on the alkenes as well as at the allylic position. This article presents an overview of these influencing factors with illustrative examples