Triarylpyrylium salts were employed as single electron photooxidants to catalyze a cyclization-endoperoxidation cascade of dienes. The transformation is presumed to proceed via the intermediacy of diene cation radicals. The nature of the diene component was investigated in this context to determine the structural requirements necessary for successful reactivity. Several unique endoperoxide stru...

Asymmetric synthesis of diarylmethylamines with high enantioselectivity (95-99% ee) was realized by use of a new C2-symmetric diene ligand, (1R,4R)-2,5-diphenylbicyclo[2.2.2]octa-2,5-diene (Ph-bod*), for the rhodium-catalyzed asymmetric arylation of N-tosylarylimines with arylboroxines.

Amorpha-4,11-diene is the precursor of the antimalarial compound artemisinin. The effect of Vitreoscilla hemoglobin (VHb) and its yeast-conform variant (VHbm) on amorpha-4,11-diene production in engineered Saccharomyces cerevisiae was investigated. First, the VHb gene was mutated to the yeast-conform variant VHbm based on step-by-step extension of a short region of the gene through a series of ...

Reactions of boranes with Te(CCPh)2 proceed via initial intermolecular 1,1-carboboration followed by either an intramolecular carboboration or an FLP addition to a second molecule of the intermediate, yielding 1-bora-4-tellurocyclohexa-2,5-diene heterocycles or tricylic derivatives of 1,4-ditellurocyclohexa-2,5-diene, respectively. The latter species is also shown to convert to the former upon ...

A bicyclobutyl that bears six carboxylic acid groups results from a trimerisation of a diene diacid in the solid state. Powder X-ray diffraction and a co-crystallisation are used to solve the structure of the diene and elucidate the stereochemistry of the bicyclobutyl, respectively.

the enzymatic hydrolysis of meso-1,7-diacetoxy-2,6-dimethylheptane 5, prepared from 2,6-dimethylhepta-1,6-diene 6, gave the (2s,6r)-7-acetoxy-2,6-dimethyl-1-heptanol 1, which was transformed to the (2r,6r)-2,6,10-trimethyl-1-undecanol 7. in this manner, the c14 side chain of a-tocopherol was synthesized from 2,6-dimethylhepta-1,6-diene 6 in only 5 steps.

Because of the importance of microbial metabolites of cholesterol as precursors in the synthesis of steroidal drugs, we decided to study the ability of Arthrobacter simplex to degrade cholesterol. Arthrobacter simplex cleaves the side chain of cholesterol in the presence of 2,2'-dipyridyl and produces 4-androstene-3,17- dione (AD) and androsta- 1,4-diene-3,17-dione(ADD). Two other intermedi...

A novel and unprecedented formation of η(4)-(vinylketene)iron complexes from η(4)-(diene)iron complexes is described herein. Treatment of η(4)-(diene)iron complexes with a Lewis acid such as GaCl3 or AlCl3 in the presence of aromatic compounds under a CO atmosphere affords η(4)-(vinylketene)iron complexes via electrophilic aromatic substitution.

A 2-diethanolamine boronyl substituted 1,3-diene has been synthesized in high yield and characterized spectroscopically as well as by X-ray crystallography. This diene has then subsequently been used in a number of fast, high yielding Diels-Alder/cross coupling reactions.

Recent evidence suggests a role for aberrant ceramide levels in the pathogenesis of cancer and chemoresistance and indicates that manipulation of tumor ceramide levels may be a useful strategy in the fight against breast cancer. This study demonstrates that alterations in the degree and position of unsaturation of bonds in the sphingoid backbone of d-erythro-N-octanoyl-sphingosine (Cer) affect ...