4957-71-5Relevant academic research and scientific papers
Total synthesis of (+)-mycalamide A
Kagawa, Natsuko,Ihara, Masataka,Toyota, Masahiro
, p. 875 - 878 (2007/10/03)
A convergent total synthesis of (+)-mycalamide A is described. A Yb(OTf)3-TMSCl catalytic system is used to synthesize a trioxadecalin ring system, which contains the right segment of mycalamide A. In addition, a tetrahydropyran ring, which is
Convergent total synthesis of (+)-mycalamide A
Kagawa, Natsuko,Ihara, Masataka,Toyota, Masahiro
, p. 6796 - 6805 (2007/10/03)
The details of a convergent total synthesis of (+)-mycalamide A are descri7bed. Yb(OTf)3-TMSCl-catalyzed cross-aldol reaction conditions are used to synthesize the right segment of mycalamide A. In this reaction, an acid-sensitive aldehyde reacts with methyl trimethylsilyl dimethylketene acetal without epimerization to provide the desired aldol adduct. Additionally, a tetrahydropyran ring, which is the left segment of mycalamide A, is prepared using a novel one-pot δ-lactone formation methodology. Both segments are constructed from a common starting material, D-mannitol. These segments are then coupled in the presence of BuLi, and the functional groups are transformed to complete the synthesis of (+)-mycalamide A.
Synthesis of optically active β,γ-unsaturated α-amino acids of α,β-unsaturated γ-amino acids. S(N)2- vs. S(N)2'-dichotomy of the Mitsunobu amination of allylic alcohols
Mulzer,Funk
, p. 101 - 112 (2007/10/02)
Novel and efficient syntheses (6-9 steps, overall yields 10-30%) are described for optically pure β,γ-unsaturated α-amino acids and α,β-unsaturated γ-amino acids, starting from (R)-isopropylidene glyceraldehyde and ethyl (S)-lactate, respectively. The key step is the Mitsunobu reaction of chiral secondary allylic alcohols with phthalimide as the nucleophile, where α,γ allylic transpositions are observed for the first time. The structure-α,γ-ratio-relationship is studied and also the stereochemistry of the allylic transposition. The α-substitution proceeds via clean S(N)2 inversion, whereas the γ-substitution corresponds to an (E)-anti attack of the nucleophilic with varying stereoselectivities.
Selective Acetate Hydrolysis of Diastereomers with Porcine Pancreatic Lipase (PPL) as an Access to Useful Chiral Building Blocks
Mulzer, Johann,Greifenberg, Stefan,Beckstett, Anne,Gottwald, Matthias
, p. 1131 - 1136 (2007/10/02)
The diastereomeric mixture of the propargylic acetates 2 was diastereomer selectively hydrolyzed with porcine pancreatic lipase (PPL) in water to give the acetate syn-2 and the alcohol anti-3, both more than 95percent diastereomerically pure.From these pr
CARBOHYDRATES AS A PRACTICAL SOURCE OF CHIRAL POLYHYDROXY ACETYLENES
Yadav, J.S.,Chander, Madhavi C.,Rao, C. Srinivas
, p. 5455 - 5458 (2007/10/02)
Syntheses of chiral polyhydroxy propargyl alcohols by employig double elimination of β-alkoxy chlorides with strong bases have been described.
Asymmetric Construction of Optically Active 3-Hydroxyalkyne Functionalities
Takano, Seiichi,Samuzi, Kiyohiro,Sugihara, Takumichi,Ogasawara, Kunio
, p. 1344 - 1345 (2007/10/02)
An efficient method for the construction of optically active 3-hydroxyalkyne functionalities has been developed using optically active α,β-epoxy alcohols readily accessible from non-chiral allyl alcohol precursors.
