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A stereoselective approach to 1,3-amino alcohols protected as cyclic carbamates: Kinetic vs. thermodynamic control

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Broustal, Garance Ariza, Xavier Campagne, Jean-Marc Garcia, Jordi Georges, Yohan Robiette, Raphaël [UCL]

Direct enantiocontrolled access to 1,3-amino alcohols protected as cyclic carbamates is described. The approach is based on the addition of a silyl dienolate to aldehydes in the presence of 10% of Carreira's catalyst (vinylogous Mukaiyama-aldol addition). The obtained delta-hydroxyesters were reduced to pent-2-ene-1,5-diols, which were converted into the corresponding dicarbamates with tosyl isocyanate. Stereoselective cyclization of these dicarbamates proceeded with 1,3-asymmetric induction under either thermodynamic or kinetic control to afford enantioselectively six-membered-ring cyclic carbamates. Calculations enabled us to rationalize the observed stereoselectivity. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).

Document type Article de périodique (Journal article) – Article de recherche
Access type Accès restreint
Publication date 2007
Language Anglais
Journal information "European Journal of Organic Chemistry" - , no. 26, p. 4293-4297 (2007)
Peer reviewed yes
Publisher Wiley-v C H Verlag Gmbh (Weinheim)
issn 1434-193X
e-issn 1099-0690
Publication status Publié
Affiliations UCL - SC/CHIM - Département de chimie
FUNDP - SCHI_GCOBS (groupe de chimie organique et bioorganique supramoléculaire)
Keywords palladium ; allylation ; 1,5-diols ; carbarnates ; aldol reactions
Links
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  15. Calculations were carried out at the B3LYP/6-311+G**//B3LYP/6-31G* level of theory, including a continuum description of the THF solvent for both the geometry optimization and the single-point calculations by using the Jaguar 6.5 program package (Jaguar 6.5, Schrödinger, LLC, New York, NY, 2005). Relative energies correspond to electronic energies. See Supporting Information for full computational details.
  16. The systematic positioning of the methyl at the 5-position and the substituent at the 6-position in the trans relative configuration was based on previous results showing that the Mukaiyama-aldol addition occurs with high anti selectivity (see ref.[5]).
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  19. The reaction of 6d was quenched after 66 h at room temp.
  20. When compound 14 with a 99:1 cis/trans ratio was resubmitted to equilibration conditions [Pd2(dba)3, (iPrO)3P in THF under reflux], a 70:30 cis/trans mixture was recovered. A longer reaction time generated significant amounts of decomposition products.
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Bibliographic reference Broustal, Garance ; Ariza, Xavier ; Campagne, Jean-Marc ; Garcia, Jordi ; Georges, Yohan ; et. al. A stereoselective approach to 1,3-amino alcohols protected as cyclic carbamates: Kinetic vs. thermodynamic control. In: European Journal of Organic Chemistry, , no. 26, p. 4293-4297 (2007)
Permanent URL http://hdl.handle.net/2078.1/37315