89872-57-1Relevant academic research and scientific papers
Synthesis of (-)-amphidinolide K fragment C9-C22
Andreou, Thanos,Costa, Anna M.,Esteban, Laia,Gonzalez, Lluisa,Mas, Gemma,Vilarrasa, Jaume
, p. 4083 - 4086 (2007/10/03)
(Chemical Equation Presented) The key fragment (2a or 2b) in a total synthesis of the cytotoxic macrolide (-)-amphidinolide K (1) has been achieved from synthons C9-C14 (3) and C15-C22 (4), which have both been prepared from glutamic acid in good overall yields.
Intramolecular reaction of a phenonium ion. Novel lactonization of 4-aryl-5-tosyloxypentanoates and 4-aryl-5-tosyloxyhexanoates concomitant with a phenyl rearrangement
Nagumo, Shinji,Ono, Machiko,Kakimoto, Yo-ichiro,Furukawa, Tsuneo,Hisano, Tomoaki,Mizukami, Megumi,Kawahara, Norio,Akita, Hiroyuki
, p. 6618 - 6622 (2007/10/03)
The novel lactonizations of methyl 4-aryl-5-tosyloxypentanoate 1 and 4-aryl-5-tosyloxyhexanoate 3 concomitant with a phenyl rearrangement are reported. The lactonizations were promoted by silica gel or heating in various solvents. By examining the effects of substituents of the aromatic ring on the reactivity, it was found that the reaction proceeded via a phenonium ion. This finding was supported by the stereochemical results for the lactonization of optical active 1. Silica gel-promoted lactonization of 1 gave only γ-lactone 2, whereas that of 3 afforded γ-lactone 4 and δ-lactone 5. These lactonizations proved to be kinetically controlled. On the other hand, when 3c was heated in CH3NO2 at 70°C, the highly selective formation of 4c was observed. Further detailed experiments confirmed that the thermal lactonization in CH3NO2 was thermodynamically controlled.
Novel lactonization induced by the phenonium ion
Nagumo, Shinji,Furukawa, Tsuneo,Ono, Machiko,Akita, Hiroyuki
, p. 2849 - 2852 (2007/10/03)
Silica gel promotes the lactonization and the concomitant aryl rearrangement of 4-aryl-5-tosyloxy pentanoates (3c-j) to give γ-lactones along with complete inversion in high yields.
Aspects of Control and Selectivity in Anion Mediated Cascade Reaction Sequences: Applications in Homochiral Synthesis.
Harrowven, David C.,Dennison, Shelagh T.,Hayward, Jonathan S.
, p. 7467 - 7468 (2007/10/02)
The transformation of the homochiral lactone 1 into the diols 3 and 6, the tetrahydrofurans 4 and 5 and a number of analogues thereof is described.
