4th EucheMs chemistry congress

Poster Session 2
s1291
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - organic chemistry
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A StereoControLLed APProACh towArdS
triCyCLiC MArine ALKALoidS uSinG
ene-yne-ene-rrM rCM CASCAde
M. GrABowSKi 1 , S. BLeChert 1
1 Technische Universität Berlin, Institut für Chemie, Berlin,
Germany
Ring-rearrangement metathesis has proven to be a powerful
synthetic tool for the construction of carbo- and heterocycles and
has been efficiently applied to various natural product syntheses
of diverse polycyclic systems. A cascade reaction with
adiastereoselective Ene-Yne-Ene-RRM RCM as a key step has
been developed for the synthesis of tricyclic indolizines.
Dienynes turned out to be challenging substrates for tandem
metathesis processes, due to a lack of selectivity-controlling
groups. A rational design for the desired pathway is shown within
this work: a cyclic ene subunit with a triple bond in an
appropriated distance for a favored RRM, and a R-group which
is not diminishing the catalyst activity, for the post-RRM RCM,
offer perfect reaction control and avoid undesired side pathways.
This attractive and versatile concept can be easily applied
for the synthesis of several lepadiformine/ cylindricine alkaloids.
Keywords: Alkaloids; metathesis; natural products; synthetic
methods; homogeneous catalysis;
4 th EucheMs chemistry congress
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AMPhiPhiLiC PoLy(BetA-PePtoid)S viA
rinG-oPeninG PoLyMeriSAtion (roP)
A. GroSSMAnn 1 , r. Luxenhofer 1
1 Technische Universität Dresden, Prof. für Makromolekulare
Chemie, Dresden, Germany
Poly(β-peptoid)s (β-POIs) are a group of peptidomimetic
polymers, which comprise a β-alanine backbone and a substituent
at the nitrogen atom. The missing hydrogen donating ability for
hydrogen bonding [1] and their proteolytic stability in comparison
to peptides [2] are properties, which make them interesting for a
variety of applications. Although the poly(β-peptoid)s have great
potential as new polymer class in different fields of research, they
are not well studied until now.
Reported routes for their preparation, like solid-phase
synthesis [3] or the living alternating copolymerization of
N-alkylaziridines and carbon monoxide, show limitations in the
DP. [1]
Another method for the synthesis of poly(β-peptoid)s is the
ring-opening polymerization (ROP) of N-substituted β-amino acid
N-carboxyanhydrides (β-NNCAs). Although living nucleophilic
ROP of α-NNCAs offers excellent synthetic control and can be
performed in a wider range of solvents, [4] publications about the
β-analogs are rare. [5, 6] Here we present a route for the synthesis
of β-NNCAs and their ROP under different conditions. We are
able to show for the first time that ROP of β-NNCAs has a living
character. [7] Thus, complex architectures and highly defined
polymers should be accessible, which is currently investigated in
our lab.
references:
1. Lin, S.; Zhang, B.; Skoumal, M. J.; Ramunno, B.; Li, X.;
Wesdemiotis, C.; Liu, L.; Jia, L. Biomacromolecules 2011,
7, 2573-2582.
2. Shuey, S. W.; Delaney, W. J.; Shah, M. C.; Scialdone, M. A.
US Pat. Appl. US20060160735, 2006.
3. Hamper, B. C.; Kolodziej, S. A.; Scates, A. M.; Smith, R. G.;
Cortez, E. J. Org. Chem. 1998, 3, 708-718.
4. Fetsch, C.; Grossmann, A.; Holz, L.; Nawroth, J. F.;
Luxenhofer, R. Macromolecules 2011, 17, 6746-6758.
5. Birkofer, L.; Kachel, H. Naturwissenschaften 1954, 576.
6. Zilkha, A.; Burstein, Y. Biopolymers 1964, 2, 147-161.
7. Grossmann, A.; Luxenhofer, R. Macromol. Rapid Commun.
in revision process.
Keywords: peptidomimetics; ring-opening polymerization;
polymers; block copolymers;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc