534-00-9Relevant articles and documents
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Heller
, p. 4858 (1952)
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Effect of regioregularity and role of heteroatom on the chiral behavior of oligo(heteroalkyl thiophene)s
Marinelli, Martina,Angiolini, Luigi,Lanzi, Massimiliano,Di Maria, Francesca,Salatelli, Elisabetta
, p. 1361 - 1376 (2020/11/23)
Novel optically active oligothiophenes bearing electron-donating chiral side chains have been prepared by synthetic methods suitable to achieve regioregular head-to-tail and head-to-head/tail-to-tail derivatives. In particular, the chiral (S)-(2-methyl)butyl moiety was linked at position 3 of the thiophene ring through heteroatoms, such as S or O, to evaluate its effect on the macro molecular aggregation and, consequently, on the chiroptical properties of the material in the solid state. The materials have been fully characterized and investigated by optical and chiroptical methods upon aggregation both from the solution and as cast films. Compared with the related head-to-tail and head-to-head/tail-to-tail poly(3-alkyl)thiophene derivatives, with the same optically active moiety directly linked to the ring and possessing a higher polymerization degree, the chiroptical properties of the newly synthesized oligomers were significant, or even better, and provided insight into the role of intrachain–interchain interactions between the heteroatom and the thienyl sulfur atom.
Straightforward synthesis of all stenusine and norstenusine stereoisomers
Mueller, Tobias,Dettner, Konrad,Seifert, Karlheinz
experimental part, p. 6032 - 6038 (2011/12/15)
All the stereoisomers of stenusine (1) and norstenusine (21) have been efficiently synthesized by the asymmetric hydrogenation of pyridines. The (2R,3S)- and (2R,3R)-isomers of 1, that are difficult to prepare, have been synthesized for the first time using a chemoenzymatic approach in eight steps with an 8 % total yield. All the target compounds were obtained in good stereochemical purity by using very simple and inexpensive reagents and auxiliaries. All the stereoisomers of the defensive alkaloids stenusine and norstenusine produced by Stenus beetles have been synthesized in a straightforward manner. The chiral (S) side chain is derived from (S)-2-methyl-1-butanol. For the difficult preparation of (R)-3-(2-methylbutyl) pyridine, a highly efficient chemoenzymatic approach was developed.
