Mannich-type reaction Catalyzed

Scheme 13 Competition studies for diastereoselective Mannich-type reaction catalyzed by...

Scheme 2.21 Mannich-type reactions catalyzed by sulfonamide-containing pyrrolidine 17 [87].

Scheme 2.23 (a) Steric interactions in the possible transition state of 13-catalyzed Mannich-type reactions, (b) The proposed, most suitable transition state of the onh-selective Mannich-type reactions catalyzed by (/ )-3-pyrrolidinecarboxylic acid (18). 

In related reactions, Snapper and Hoveyda et al. reported an asymmetric version of Mannich-type reactions catalyzed by silver acetate.38,39 Propargyl imines proved to be susceptible to nucleophilic addition of sily lenol ethers derived from acetate esters in the... 

Akiyama T, Itoh J, Yokota K, Fuchibe K (2004) Enantioselective Mannich-type reaction catalyzed by a chiral Brpnsted acid. Angew Chem Int Ed Engl 43 1566-1568... 

Akiyama T, Morita H, Itoh J, Fuchibe K (2005a) Chiral Brpnsted acid catalyzed enantioselective hydrophosphonylation of imines asymmetric synthesis of alpha-amino phosphonates. Qrg Lett 7 2583-2585 Akiyama T, Saitoh Y, Morita H, Fuchibe K (2005b) Enantioselective Mannich-type reaction catalyzed by a chiral Bronsted acid derived from TADDOL. Adv Synth Catal 347 1523-1526... 

Achari B, Mandal SB, Dutta PK, Chowdhury C (2004) Synlett 2004 2449 Aggarwal VK, Belfield AJ (2003) Catalytic asymmetric Nazarov reactions promoted by chiral Lewis acid complexes. Org Lett 5 5075-5078 Akiyama T, Itoh J, Fuchibe K (2006c) Adv Synth Catal 348 999 Akiyama T, Itoh J, Yokota K, Fuchibe K (2004) Enantioselective Mannich-type reaction catalyzed by a chiral Brpnsted acid. Angew Chem Int Ed Engl 43 1566-1568... 

Mitsumori, S. Zhang, H. Ha-Yeon Cheong, P Honk, K. N. Tanaka, R Barbas, C. F. Direct asymmetric anti-Mannich-type reactions catalyzed by a designed amino acid, 7. Am. Chem. Soc. 2006,128, 1040-1041. 

A possible mechanism for the present reaction is shown in Scheme 9. It should be noted that dehydration accompanied by imine formation and successive addition of a vinyl ether proceed smoothly in aqueous solution and that the first aqueous Mannich-type reaction catalyzed by Ln(OTf)3 has been developed [57]. Use of Ln(OTf)3> a water-tolerant Lewis acid, is key and essential in this reaction. 

Eftekhari-Sis, B., Abdollahifar, A., Hashemi, M.M. and Zirak, M. 2006. Stereoselective synthesis of 3-amino ketones via direct Mannich-type reactions, catalyzed with Zr0C12-8H20 under solvent-free conditions. Eur. J. Org. Chem. 5152. 

Yao et al. [92] reported one-pot synthesis of flavanone 64 via Mannich type reaction catalyzed by molecular iodine. A simple workup and the high compatibihty of functional groups made this an attractive synthetic approach to access flavanone derivatives (Scheme 10.46). The three-component Mannich reaction of aldehyde, amine, and enolizable ketone to obtain the P-aminocaibottyl compounds has been known, bnt when the Mannich reaction of benzaldehyde, aniline, and 2-hydroxyacetophenone had been explored in the presence of iodine, no trace of p-aminocaiboi l compound is observed and flavanone was formed as the sole product in moderate yield. 

Table 13.3 Three-component Mannich-type reaction catalyzed by Yb(OTf)3...

Akiyama, T., Itoh, J. and Fuchibe, K., Mannich-type reaction catalyzed by HBF4 in water effect of the loading of surfactant, Synlett, 2002, 1269-1272. 

Scheme 1.35 Enantioselective Mannich-type reactions catalyzed by chiral BBA (30).

Scheme 11,3 Enantioselective Mannich-type reaction catalyzed by TADDOL-based phosphoric...

As already mentioned, a very high positive effect of pressure on the asymmetric organocatalytic Mannich-type reaction catalyzed by proline was observed by Hayashi (Scheme 21.5 and Table 21.2) (20). 

Distinct from the classical aminocatalysis, Tsogoeva and co-workers documented the first example of enol activation in the typical Mannich-type reaction catalyzed by primary amine-thiourea 63 (Scheme 5.48) [76], The isotope experiments exclude the involvement of a covalent enamine/iminium intermediate and theoretical calculation proves an enol type transition state in this reaction. 

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