Continuous Enantioselective Kinetic Resolution of Terminal Epoxides Using Immobilized Chiral Cobalt-Salen Complexes

Abstract

Jacobsen’s cobalt-salen complex was covalently immobilized on polymer carriers that are part of different technical setups (polymer powder, composite Raschig rings, PASSflow microreactors) and employed for the enantioselective ring opening of terminal epoxides with water and phenols. The polymer-supported catalysts showed good activity and stereoselectivity and could be used repeatedly after a simple reactivation protocol in both batch as well as continuous-flow modes.

catalysis - immobilization - continuous-flow processes - enantioselective synthesis - microreactor - salen

References

For recent reviews on immobilized catalysts, see:

<A NAME="RZ22306SS-1A">1a</A> Immobilised Catalysts, In Topics in Current Chemistry   Vol. 242:  Kirschning A. Springer; Berlin: 2004. 

<A NAME="RZ22306SS-1B">1b</A> Solodenko W. Frenzel T. Kirschning A. In Polymeric Materials in Organic Synthesis and Catalysis   Buchmeiser MR. Wiley-VCH; Weinheim: 2003.  p.201-240  

<A NAME="RZ22306SS-1C">1c</A> Li C. Catal. Rev.-Sci. Eng.  2004,  46:  419 

<A NAME="RZ22306SS-1D">1d</A> Xia QH. Ge HQ. Ye CP. Liu ZM. Su KX. Chem. Rev.  2005,  105:  1603 

<A NAME="RZ22306SS-2A">2a</A> Jas G. Kirschning A. Chem. Eur. J.  2003,  9:  5708 

<A NAME="RZ22306SS-2B">2b</A> Kirschning A. Solodenko W. Mennecke K. Chem. Eur. J.  2006,  12:  5972 ; and references therein

<A NAME="RZ22306SS-3A">3a</A> Yoon TP. Jacobsen EN. Science  2003,  299:  1691 

<A NAME="RZ22306SS-3B">3b</A> Larrow JF. Jacobsen EN. Top. Organomet. Chem.  2004,  6:  123 

<A NAME="RZ22306SS-4">4</A> Annis DA. Jacobsen EN. J. Am. Chem. Soc.  1999,  121:  4147 

For recent publications on immobilized chiral salen complexes, see:

<A NAME="RZ22306SS-5A">5a</A> Reger TS. Janda KD. J. Am. Chem. Soc.  2000,  122:  6929 

<A NAME="RZ22306SS-5B">5b</A> Heckel A. Seebach D. Helv. Chim. Acta  2002,  85:  9130 

<A NAME="RZ22306SS-5C">5c</A> Holbach M. Weck M. J. Org. Chem.  2006,  71:  1825 ; and references therein

<A NAME="RZ22306SS-6A">6a</A> Kirschning A. Altwicker C. Dräger G. Harders J. Hoffmann N. Hoffmann U. Schönfeld H. Solodenko W. Kunz U. Angew. Chem. Int. Ed.  2001,  40:  3995 

<A NAME="RZ22306SS-6B">6b</A> Kunz U. Schönfeld H. Solodenko W. Jas G. Kirschning A. Ind. Eng. Chem. Res.  2005,  44:  8458 

<A NAME="RZ22306SS-7">7</A>

The loading with salen ligand was determined by weight increase and combustion analysis.

<A NAME="RZ22306SS-8A">8a</A> Tokunada M. Larrow JF. Kakiuchi F. Jacobsen EN. Science  1997,  277:  936 

<A NAME="RZ22306SS-8B">8b</A> Schaus SE. Brandes BD. Larrow JF. Tokunada M. Hansen KB. Gould AE. Furrow ME. Jacobsen EN. J. Am. Chem. Soc.  2002,  124:  1307 

<A NAME="RZ22306SS-9">9</A> Ready JM. Jacobsen EN. J. Am. Chem. Soc.  1999,  121:  6086 

<A NAME="RZ22306SS-10">10</A> Furrow ME. Schaus SE. Jacobsen EN. J. Org. Chem.  1998,  63:  6776 

<A NAME="RZ22306SS-11">11</A> Hodge and co-workers were one of the first groups that combined solid-phase assisted organic synthesis with continuous-flow techniques; Hodge P. Sung DWL. Stratford PW. J. Chem. Soc., Perkin Trans. 1  1999,  2335 ; and references cited therein

For related important work in this field refer to:

<A NAME="RZ22306SS-12A">12a</A> Saaby S. Knudsen KR. Ladlow M. Ley SV. Chem. Commun.  2005,  2909 

<A NAME="RZ22306SS-12B">12b</A> Yoswathananont N. Nitta K. Nishiuchi Y. Sato M. Chem. Commun.  2005,  40 

<A NAME="RZ22306SS-13">13</A> Rubin AE. Tummala S. Both DA. Wang C. Delaney EJ. Chem. Rev.  2006,  106:  2794 

<A NAME="RZ22306SS-14">14</A> Ready JM. Jacobsen EN. J. Am. Chem. Soc.  2001,  123:  2687 

<A NAME="RZ22306SS-15">15</A> Kawakami Y. Asai T. Umeyama K. Yamashita Y. J. Org. Chem.  1982,  47:  3581