The total synthesis of (-)-ecklonialactone B as well as the 9,10-dihydro derivative by two different strategies is reported. The catalytic asymmetric Claisen rearrangement of Gosteli-type allyl vinyl ethers delivered elaborated α-keto ester building blocks. Ring-closing metatheses, including a notable diastereotopos-differentiating variant, a B-alkyl Suzuki-Miyaura cross-coupling reaction and a regio- and diastereoselective last-step epoxidation are key contributors.

The enantioselective synthesis of (-)-9,10-dihydroecklonialactone B is described. The catalytic asymmetric Claisen rearrangement of a Gosteli-type allyl vinyl ether was utilized to afford an acyclic α-keto ester building block endowed with functionality amenable to the preparation of the carbocyclic target molecule by suitable postrearrangement transformations: A highly diastereoselective Corey-Bakshi-Shibata reduction of a β-chiral α-keto ester and a reductive homologation of an α-hydroxy ester. A transprotection tactic by a chemoselective intramolecular 6-exo-trig iodoetherification enabled regioselective ring-closing alkene metatheses to afford the 5- as well as the 14-membered ring, however, with mixed success in terms of E/Z selectivity.

AIethods are described for the determination of benzidine a n d of $naphthylamine in (1) t h e atmnsphere, (2) plant deposits, ( 3 ) clothing. .\lthough t h e methods are primarily designed for cases xvhere it is known t h a t either benzidine or jj-naphthylamine is the sole ainine present, qualitative and senii-quantitative methods are also inclutled S I ) a s to detect and make allowance for the presence o f other aniiiies such as homologues or analogurs 111 t h e case of lieiizidine or of aniline or r-naplithylamine i n the case of p-naphthylaniine.

Results from efforts aimed at the synthesis of polyhydroxylated jatropha-5,12-dienes are unveiled. An apparently pre-qualified plot consisting of successive aldol addition and ring-closing metathesis was pursued in order to construct the fully oxidized trans-bicyclo[10.3.0]pentadecane scaffold of naturally occurring jatrophanoids.

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