Catalysts primary amine

Secondary and Primary Amine Catalysts for Iminium Catalysis... 

In order to find a highly stereospedfic, homogeneous catalyst for the polymerization of propylene oxide, we selected the organometallic compound-primary amine catalyst system which exhibited excellent stereospecificity in the polymerization of acetaldehyde. 

Hypothesizing that primary amine catalysts, due to their reduced steric requirements, might be suitable for the activation of ketones, we studied various salts of a-amino acid esters. (For pioneering use of primary amine salts in asymmetric iminium catalysis involving aldehyde substrates, see Ishihara and Nakano 2005 Sakakura et al. 2006 for the use of preformed imines of a, 3-unsaturated aldehydes and amino acid esters in diastereoselective Michael additions, see Hashimot et al. 1977.) We have developed a new class of catalytic salts, in which both the cation and the anion are chiral. In particular, valine ester phosphate salt 35 proved to be an active catalyst for the transfer hydrogenation of a variety of a, 3-unsaturated ketones 36 with commercially available Hantzsch ester 11 to give saturated ketones 37 in excellent enantiose-lectivities (Scheme 28 Martin and List 2006). 

Bass JD, Solovyov A, Pascal AJ, Katz A (2006) Acid-base bifunctional and dielectric outer-sphere effects in heterogeneous catalysis A comparative investigation of model primary amine catalysts. J Am Chem Soc 128 3737... 

Quite recently, List and coworkers observed that when hydrogen peroxide is used as an oxidant, the same reaction furnishes stable and isolable cyclic peroxyhemike-tals [26]. When using the primary amine catalyst 20-trichloroacetic acid (10 mol%), the oxidation of both linear and branched acyclic enones with aqueous hydrogen peroxide (3 equiv) at 30 °C in dioxane gave the peroxyhemiketals 26 in reasonable yields with high enantioselectivities (94—95% ee) (Scheme 5.20). Cyclic peroxyhemiketals were further transformed via a simple protocol (treatment with 1 N NaOH)... 

By employing the primary amine catalyst 160, Zhong and coworkers developed the tandem Michael-Henry reaction of ketones with nitroalkenes to provide highly functionalized chiral hexanes and pentanes with high diastereo- and enantioselec-tivity [49]. The selected examples depicted in Scheme 9.56 show that, in the presence of 160 (10-15 mol%), various Michael donors and nitroalkenes smoothly underwent the tandem reaction with almost quantitative yield and extremely high enantios-electivity with the complete diastereoselectivity of the products. Further details of this reaction can be seen in Section 10.4. 

Scheme 3.19 The Michael addition of 1,3-dicarbonyl compounds to enones catalyzed by bifunctional primary amine catalysts.

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