4th EucheMs chemistry congress

tuesday, 28-Aug 2012
s763
chem. Listy 106, s587–s1425 (2012)
organic Chemistry, Polymers – i
organometallic Chemistry, catalysis, new frontiers – V
o - 2 2 0
tAMinG the reACtivity of orGAnoMetALLiC
reAGentS in ASyMMetriC CAtALySiS: new
viStAS in CoPPer(i) CheMiStry
S. r. hArutyunyAn 1 , f. CAPrioLi 1 , M. AdriAAn 1 ,
M. AShoKA 1
1 University of Groningen, Stratingh Institute, Groningen,
Netherlands
The addition of highly reactive organometallic reagents to
functionalized substrates is in principle one of the most
straightforward methods to construct asymmetric carbon-carbon
bond. Copper(I) based catalysts have been used as the
synthetic tool par excellence to achieve 1,4-selectivity and
SN2'-substitution with reactive organometallic compounds such
as organozinc, aluminium and Grignard reagents.
This talk will focus on our current discovery which shows
that the longstanding paradigm of copper(I) based catalysts
favouring 1,4-selectivity over 1,2-selectivity in the addition of
Grignard reagents is not fully justified and that highly valuable
chiral tertiary and secondary alcohols can be now accessed via
copper(I) chemistry. 2 In this talk it will be shown how, employing
chiral copper phosphine complex, catalytic enantioselective
synthesis of tertiary alcohols can also be achieved for the first time
using Grignard reagents with both enones, enals and alkyl aryl
ketones with near perfect stereocontrol. Beneficially, the catalytic
system provides already the highest level of enantioselectivity
using the chiral ligand with e.r. of only 60:40. Mechanistic studies,
structure of the active species and scope of the reaction will be
discussed.
Keywords: asymmetric catalysis; tertiary alcohol; copper
catalysis; ferrocenyl diphosphine; 1,2-addition;
General synthetic methods – i
4 th EucheMs chemistry congress
o - 2 1 3
ASyMMetriC orGAnoCAtALytiC doMino
reACtionS
d. enderS 1
1 RWTH Aachen University, Organic Chemistry, Aachen,
Germany
The research field of organocatalysis has developed rapidly
since about the turn of the millennium and can now be seen as a
third pillar of asymmetric catalysis beside metal and biocatalysis.
Numerous basic organocatalytic protocols for very efficient and
highly stereoselective carbon-carbon and carbon-heteroatom bond
formations are now part of the strategic arsenal of synthetic
chemistry.
In this short lecture the development of simple, triple and
even quadruple organocatalytic domino (cascade) reactions [1] using
i.a. diphenyl prolinol-TMS-ether as catalyst will be presented.
Some applications of these organocascade reactions in the
short and efficient asymmetric synthesis of thiadecalines [2] ,
3H-pyrrolo[1,2-a]indole-2-carbaldehydes 3 , novel GABA
derivatives [4] , polyfunctionalized 3-(cyclohexenyl-methyl)-indoles [5]
and tetracyclic indol structures will be reported.
references:
1. For reviews from our group, see:
a) A. Grossmann, D. Enders, Angew. Chem. Int. Ed. 2012,
51, 314;
b) C. Grondal, M. Jeanty, D. Enders, Nature Chemistry
2010, 2, 167.
c) D. Enders, C. Grondal, M. R. M. Hüttl, Angew. Chem.
Int. Ed. 2007,46, 1570.
2. D. Enders, B. Schmid, N. Erdmann, G. Raabe, Synthesis
2010, 2271.
3. D. Enders, C. Wang, G. Raabe, Synthesis 2009, 4119.
4. D. Enders, C. Wang, J. W. Bats, Angew. Chem. Int. Ed.
2008, 47, 7539.
5. D. Enders, C. Wang, M. Mukanova, A. Greb, Chem.
Commun. 2010, 46, 2447.
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc