An asymmetric synthetic route for 1-iodofarnesane, a key intermediate for tocopherol sidechain synthesis, startingfrom (+)-(R)-citronellal was developed. 1-Iodofarnesane was prepared through eight steps in about 50% overall yield, and asymmetric transfer hydrogenation of the enal with a chiral organocatalyst was conducted as a stereoinduction step. To measure the stereoinduction level and optical
Synthetic analogs of phytanic acid and their effect on human hepatic cholesterol esterase in vitro
作者:É. P. Serebryakov、G. V. Kryshtal’、G. M. Zhdankina、A. G. Nigmatov、V. V. Tertov、L. V. Filatova
DOI:10.1007/s11094-006-0050-6
日期:2006.1
Ten acyclic isoprenoid fatty acids were synthesized and tested in vitro as possible regulators of the cholesterol/cholesteryl alkanoate ratio in blood serum lipoproteins. Racemic C20 analogs of (3R/S,7R, 11R)-3,7,11,15-tetramethylhexadecanoic (phytanic) acid proved to be powerful activators of human liver cholesterol esterase (HLCE) in vitro. Achiral (E,E)-5,9,13-trimethyltetradeca-4,8,12-trienoic (farnesylacetic) acid, a low-toxicity antiulcerative substance, also significantly accelerates the HLCE-catalyzed hydrolysis of cholesteryl palmitate.
A unique electron-accepting analog of vitamin K1 found in photosystem I in several species of oxygenic photosynthetic microorganisms was confirmed to be 5'-hydroxyphylloquinone (1) through stereo-uncontrolled synthesis. Furthermore, the stereochemistry of 1 obtained from Synechococcus sp. PCC 7942 was assigned to be 5'S using proline-catalyzed stereocontrolled reactions.
Total Synthesis of (2<i>RS</i>)-α-Tocopherol through Ni-Catalyzed 1,4-Addition to a Chromenone Intermediate
作者:Andreas Ole Termath、Janna Velder、René T. Stemmler、Thomas Netscher、Werner Bonrath、Hans-Günther Schmalz
DOI:10.1002/ejoc.201402240
日期:2014.6
A novel strategy for the total synthesis of α-tocopherol (“vitamin E”) was elaborated on the basis of the conjugate addition of AlMe3 (as a methyl anion equivalent) to a 2-substituted chromenone. Starting from trimethylhydroquinone and (R,R)-hexahydrofarnesol, the required chromenone substrate was efficiently prepared in a short sequence exploiting a TiCl4-mediated Fries rearrangement and a KOtBu-induced