4th EucheMs chemistry congress

Poster Session 2
s1316
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - organic chemistry
P - 0 9 0 7
SyntheSiS of ferroCene-BASed MoLeCuLAr
wireS
n. KrAuSSe 1
1 Institut für Organische Chemie, Leibniz Universität Hannover,
Hannover, Germany
Email: holger.butenschoen@mbox.oci.uni-hannover.de
Molecular wires of the oligo(phenylene ethynylene) (OPE)
type have rigid structures with fixed molecular lengths. To
introduce limited conformational flexibility we are interested in
replacing some 1,4-phenylene units by 1,1'-ferrocenylidene
groups. Different molecular wires with two or three ferrocene
units with tert-butylsulfanyl groups as anchoring groups were
obtained via Sonogashira coupling reaction or Negishi coupling
[1, 2] reaction.
In search for different anchoring groups we noted that
Wandlowski reported about molecular wires with nitrile groups. [3]
First examples for nitrile-terminated molecular wires based on
ferrocene have recently been prepared.
references:
1. J. Ma, M. Vollmann, H. Menzel, S. Pohle, H. Butenschön,
J. Inorg. Organomet. Polym. 2008, 18, 41–50.
2. I. Baumgardt, H. Butenschön, Eur. J. Org. Chem. 2010,
1076–1087.
3. A. Mishchenko, L. Zotti, D. Vonlanthen, M. Bürkle,
F. Pauly, J. Cuevas, M. Mayor, T. Wandlowski,
J. Am. Chem. Soc. 2011, 133, 184–187.
Keywords: Ferrocene; OPE; Molecular Wire;
4 th EucheMs chemistry congress
P - 0 9 0 8
APPLiCAtion of ChirAL rutheniuM CAtALyStS
in enAntioSeLeCtvie oLefinMetAtheSiS
C. Kuhn 1 , C. huLot 1 , d. SChLeSiGer 1 , A. BerGer 1 ,
S. BLeChert 1
1 Technical University Berlin, Institute of Chemistry, Berlin,
Germany
The development of chiral Ru-based olefin metathesis
catalysts to obtain high enantioselectivities has been shown to be
a challenge in the field of asymmetric olefin metathesis. Recently
we reported the development of highly active and chiral Ru-based
metathesis catalysts with high stability which show excellent
results in asymmetric ring-opening cross metathesis (AROCM)
as well as in enantioselective ring-rearrangement metathesis
(eRRM).
Various cross partners such as allylsilanes, allyl alcohol,
allyl chloride and allyl tert-butyl carbonate can be used in the
AROCM of norbornene derivatives providing products with high
E-selectivity and excellent enantioselectivities up to 93%ee. The
AROCM products with allyl silanes can further be transformed
in a Sakurai reaction into highly enantiomerically enriched
bicyclo[3.2.0]heptanones with 4 stereogenic centers which
contain a new built 4-membered ring.
Ring-rearrangement metathesis is a well-known and
powerful method to construct complex carbo- and heterocycles in
a domino process that has been used in several natural product
syntheses. Nevertheless efficient enantioselective RRM still
remain challenging.
Here the first examples of asymmetric Ene-Yne-RRM based
on chiral Ru-metathesis catalysts were performed providing
excellent enantioselectivities up to 94%ee giving
tetrahydropyridines selectively.
Keywords: metathesis; domino reactions; ruthenium;
enantioselectivity; regioselectivity;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc