4th EucheMs chemistry congress

Poster Session 1
s1059
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - organic chemistry
P - 0 3 9 5
APPLiCAtionS of hyPervALent iodine
reAGentS in the PrePArAtion of SynthetiC
quinoidS
B. Meier 1 , G. LAiner 1 , A. PreSSer 1
1 Karl-Franzens-Universität Graz, Pharmaceutical
Sciences /Pharmaceutical Chemistry, Graz, Austria
Naturally occurring quinones and quinols are very
interesting chemical leads with several biological activities [1] . To
prepare these promising compounds a number of procedures were
found in the literature [2] , but all of them have some restrictions.
As part of a program directed at the discovery of new
antiprotozoal agents, we were interested in the facile construction
of the p-quinol skeleton. Hypervalent iodine reagents
(phenyliodine(III) diacetate, phenyliodine(III) bis-trifluoroacetate,
etc.) are a versatile oxidation tool meeting the concept of green
chemistry because of their low toxicity, easy handling, safety and
ready availability [3] .
Here we report a practical and general method to prepare a
series of quinol-derivatives using hypervalent iodine reagents.
Commercial available para-substituted phenols and their briefly
modified derivatives acted as starting material.
references:
1. Wang WS, Lu P, Duan CH, Feng JC. Nat Prod Res 24,
370-4 (2010).
2. a) Fischer A, Henderson GN. Tetrahedron Letters 24,
131–4 (1983);
b) Araki S, Katsumura N, Kawasaki K, Butsugan Y.
J Chem Soc Perk Trans 1 3, 499-500 (1991);
c) Wells G, Berry JM, Bradshaw TD, Burger AM, Seaton
A, Wang B, Westwell AD, Stevens MFG. J Med Chem
46, 532-41 (2003);
d) Kawakami J, Nakamoto K, Nuwa S, Handa S, Miki S.
Tetrahedron Letters 47, 1201–3 (2006);
e) Clive DLJ, Sunasee R, Chen Z. Org Biomol Chem 6,
2434-41 (2008).
3. Encyclopedia of Reagents for Organic Synthesis
Copyright © 2005 John Wiley & Sons, Ltd.
Keywords: Hypervalent iodine; dearomatization; p-quinol;
antiprotozoal;
4 th EucheMs chemistry congress
P - 0 3 9 6
hiGhLy diAStereoSeLeCtive Method
for the PrePArAtion of 1,2-ALKenyL dioLS
t. MeJuCh 1 , i. MAreK 1
1 Technion Israel Institute of Technology, Schulich Faculty of
Chemistry, Haifa, Israel
The development of new and highly diastereoselective
processes for the creation of carbon-carbon and carbon-heteroatom
bonds is one of the major targets in chemical synthesis. In contrast
to tertiary stereocenters, the construction of quaternary
stereocenters, that are carbon centers bearing four different
non-hydrogen substituents, represents one of the most challenging
and dynamic areas in organic synthesis. The state-of-the-art is the
asymmetric construction of such quaternary stereocenters in
non-cyclic systems (more complicated due to the number of
degrees of freedom associated with these structures). Most of the
current methods produce only one carbon-carbon bond per
chemical step and, therefore, may suffer from low efficiency.
Recently, we have developed highly diastereoselective and
efficient process for the construction of 1,2-alkenyl diol moiety
from simple alkynyl ethers through the formation of several
carbon-carbon bonds in one chemical step (T. Mejuch, M.
Botoshansky, I. Marek, Org. Lett. 2011, 13, 3604; T. Mejuch, B.
Dutta, M. Botoshansky, I. Marek, Org. Biomol. Chem. 2012,
Advance Article doi: 10.1039/C2OB25121C). The
stereochemistry was rationalized through a Zimmerman-Traxler
transition state, in which the bulky group of the carbonyl occupies
a pseudo-axial position to avoid one gauche interaction (N.
Gilboa, H. Wang, K. H. Houk, I. Marek, Chem. Eur. J. 2011, 17,
8000).
Keywords: allylation; carbonyl compounds; diastereoselective
synthesis;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc