29949-29-9Relevant academic research and scientific papers
Total Synthesis of the Cardiotonic Steroid (+)-Cannogenol
Watanabe, Shogo,Nishikawa, Toshio,Nakazaki, Atsuo
, p. 3605 - 3614 (2021)
The total synthesis of (+)-cannogenol, an aglycon common to various biologically important cardiotonic glycosides, has been achieved. Synthesis of the versatile intermediate involves Mizoroki-Heck and intramolecular Diels-Alder reactions from the enantiomerically pure CD-ring segment, newly prepared in a multidecagram scale this time. Total synthesis by the site-selective transformations of the versatile intermediate demonstrated the applicability of our synthetic approach.
De Novo Synthesis of Possible Candidates for the Inagami-Tamura Endogenous Digitalis-like Factor
Nakazaki, Atsuo,Hashimoto, Keiko,Ikeda, Ai,Shibata, Takahiro,Nishikawa, Toshio
, p. 9097 - 9111 (2017/09/11)
De novo synthesis of possible candidates for the Inagami-Tamura endogenous digitalis-like factor (EDLF) was achieved to validate a previously proposed structure. Our synthetic approach involves a highly regio- and diastereoselective Mizoroki-Heck reaction and a Friedel-Crafts-type cyclodehydration to construct steroidal tetracycle 14 as a versatile common intermediate leading to seven 2,14β-dihydroxyestradiol analogues 1a-c, 2a-c, and 3 as possible candidates. By comparing the potency of inhibitory activity against Na+/K+-ATPase between the synthesized candidates and the EDLF, it was found that the proposed structure is not likely to be a true structure of the Inagami-Tamura EDLF.
Pentadienyl type lithium and potassium species: The regioselectivity of their reactions with electrophiles
Schlosser,Zellner,Leroux
, p. 1830 - 1836 (2007/10/03)
Seven structurally distinct pentadienyl type lithium and potassium compounds were screened against a variety of electrophiles in order to assess the regioselectivity of the trapping reactions. Organoborates and analogs thereof (fluorodimethoxyborane) proved to be perfectly regioreliable attacking only unsubstituted terminal positions and thus providing, after oxidation, exclusively primary allylic alcohols. 2,4-Pentadienyllithiums or -potassiums, that carry a methyl group at the 1- or 3-position, exhibit the same extreme regioselectivity towards halotrialkylsilanes or carbon dioxide. Although the unsubstituted parent compounds combine with such electrophiles still preferentially at the terminal position, considerable proportions of branched products are concomitantly formed as well (1/3-attack ratios ranging from 2:1 to >20:1). Hydroxyalkylating and alkylating reagents such as formaldehyde, oxirane or butyl iodide invariably afford regioisomeric mixtures generally varying in composition between 3:1 and 1:3. The condensation reaction with halotrialkylsilanes appears to follow a concerted (SN2-like) rather than an addition/elimination (ate complex-mediated) mechanism.
TRANSITION METAL-CATALYZED SYNTHESES OF ORGANIC ACIDS BY CHELATION-PROMOTED REGIOSELECTIVE DOUBLE BOND INSERTION
Chiusoli, G. Paolo,Salerno, Giuseppe,Giroldini, William,Pallini, Luciano
, p. C16 - C20 (2007/10/02)
The rhodium- or nickel-catalyzed reaction of vinylic halides with alkali salts of 3-butenoic acids leads to regioselective formation of dienoic acids, containing 3,5-conjugated double bonds.Monoarylacetylenes also react with 3-butenoic acids in a rhodium-
