Co-reporter:Kenichi Harada, Akiko Imai, Kazuharu Uto, Rich G. Carter, Miwa Kubo, Hideaki Hioki, Yoshiyasu Fukuyama
Tetrahedron 2015 Volume 71(Issue 15) pp:2199-2209
Publication Date(Web):15 April 2015
DOI:10.1016/j.tet.2015.02.090
The formal synthesis of jiadifenin, which has potent neurotrophic activity, was accomplished using intramolecular Mizoroki–Heck reaction and tandem Tsuji–Trost cyclization/lactonization reaction as key steps. Intramolecular Mizoroki–Heck reaction was employed for the construction of the A ring moiety accompanied with the formation of C9 quaternary center, which was dramatically promoted by protic solvent. Tandem Tsuji–Trost cyclization/lactonization reaction was applied to the successive cyclization of the BC ring system to elaborate under conditions, Pd(OAc)2, (±)-BINAP, and LiOAc in t-BuOH, leading to Theodorakis's intermediate followed by a few functionalizations.
Co-reporter:Kenichi Harada, Chiharu Arioka, Akina Miyakita, Miwa Kubo, Yoshiyasu Fukuyama
Tetrahedron Letters 2014 Volume 55(Issue 43) pp:6001-6003
Publication Date(Web):22 October 2014
DOI:10.1016/j.tetlet.2014.09.040
Efficient synthesis of honokiol (1) was accomplished using two kinds of Suzuki–Miyaura reactions. The first Suzuki–Miyaura reaction was employed to couple 2-bromophenol (6) with 4-hydroxyphenylboronic acid (5), giving rise to biphenol 4, and the second coupling was used to introduce allyl groups at 5- and 3′-positions of honokiol. The total synthesis of 1 was completed in 74% yield over five steps from 6, or in 83% yield over four steps from biphenol 4.Total 74% over 5 steps or 83% over 4 steps.