The application of alkaline metal(Ca, Sr, Ba) complex as catalyst in organic chemistry 张文全 1

introduction Alkaline earth metals are very attractive because they are abundant and ubiquitous elements in nature and form safe compounds compared with other heavy transition metals. However, their positive use as catalysts in asymmetric synthesis is still limited. Their strong Brønsted basicity and mild Lewis acidity can influence their catalytic activity, as well as chiral modification of a complex in a positive manner. 2

calcium The application of calcium complex in organic chemistry will show follow 3

First example of an optically active calcium catalyst Shiro Ikegami, Tetrahedron Letters 41 (2000) 2165 Baylis–Hillman Reaction 62 yield% 56 ee% 4

G. Kumaraswamy, Tetrahedron Letters 42 (2001) 8515 Michael Reactions 5

G. Kumaraswamy, Adv. Synth. Catal. 2005, 347, 867 6

18-96ee% 50-quant yield% Shu Kobayashi, Angew. Chem. Int. Ed. 2009, 48,

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Shu Kobayashi, Tetrahedron: Asymmetry 21 (2010)

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ligand real catalyst Shu Kobayashi, J. AM. CHEM. SOC. 2010, 132,

Shu Kobayashi, J. AM. CHEM. SOC. 2007, 129, 5364 Shu Kobayashi, J. AM. CHEM. SOC. 2008, 130, Shu Kobayashi, O.L. 2008, Vol. 10, No. 5,

Catalytic cycle of the 1,4-addition reaction 13

Two Possible Reaction Mechanisms of the [3 + 2] Cycloaddition Reaction 14

so stepwise is possible cis/trans=2/1 15

Meike Niggemann, Angew. Chem. Int. Ed. 2010, 49, 3684 Friedel-Craft Reaction electrion-rich AromaticArH = 16

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cat: Kazuaki Ishihara, Angew. Chem. Int. Ed. 2010, 49, 3823 Mannich Reaction 18

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Aliphatic N-Boc imine can react, good yield but low ee Shu Kobayashi, J. Org. Chem. 2010, 75,

epoxidation G. Kumaraswamy, Tetrahedron: Asymmetry 14 (2003)

electrion-rich Aromatic etc Meike Niggemann, Chem. Eur. J. 2010, 16, Hydroarylation of Alkenes 22

Michael S. Hill, J. AM. CHEM. SOC. 2005, 127, 2042 Hydroamination 23

aminoalkeneproductTime(h)Temp.( o C)Conv.% 24

Peter W. Roesky, Organometallics 2007, 26,

regioselective products in most cases, giving rise to only the A-ol isomer. However, when a nitrogen functionality is present, the isomeric ratio of products is altered to give mixtures of the favored 6-ol isomer and the disfavored B-ol regioisomer. such as: Pictet-Spengler Reaction 26

James P. Stambuli, ORGANIC LETTERS, 2008, Vol. 10, No. 22, 5289 James P. Stambuli, J. Org. Chem. XXXX, XXX, 000 Ketone: 27

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Anthony G. M. Barrett, Michael S. Hill, O. L. 2007, Vol. 9, No. 2, 331 Tischenko Reaction How to start the catalic cycle? being continuing to study 29

Anthony G. M. Barrett, Michael S. Hill, Organometallics 2007, 26, 2953 Hydrophosphination 30

Anthony G. M. Barrett, Michael S. Hill, Organometallics 2008, 27,

Ryoji Noyorib, Tetrahedron Letters 42 (2001) 4669 Aldol Reaction 32

Jieping Zhu, O. L. XXXX, Vol. xx, No. x 33

strontium Need to develop new ligand 34

S. Kobayashi, Angew. Chem. Int. Ed. 2009, 48, 5927 S. Kobayashi,Bull. Chem. Soc. Jpn. Vol. 82, No. 9, 1083 Mannich 35

solvent effect Conditions A: DMF, RT, 17 h, Ar=2,5-xylyl. Conditions B: Ligand 4 (11 mol%), THF, RT, 24 h, Ar=p-NO2-C6H4. The addition of ligand 4 generally increased the syn selectivity 36

this is the first example of a catalytic asymmetric Mannich-type reaction of a sulfonylimidate 37

Ligand: Shuj Kobayashi, J. AM. CHEM. SOC. 2008, 130, 2430 Michael Reactions 38

donor acceptor ligand Shu Kobayashi, Chemistry Letters Vol.38, No.3 (2009) 39

Motomu Kanai, Masakatsu Shibasaki, J. AM. CHEM. SOC. 2010, 132,

41

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barium Barium has the largest ionic radius, which often form oligomer Like: 43

44 Motomu Kanai, Angew. Chem. 2009, 121, 1090 Diels–Alder-type reaction

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Masakatsu Shibasaki, Tetrahedron Letters 39 (1998) 5561 Aldol ReactionFirst example of an optically active alkaline meta catalyst up to 70 ee% 46

catalytic cycle 47

Shu Kobayashi, J. AM. CHEM. SOC. 2006, 128,

Masakatsu Shibasaki, J. AM. CHEM. SOC. 2009, 131,

ligand Shu Kobayashi, Chem. Commun., 2007, 1236 Mannich reaction 50

Masakatsu Shibasaki, O. L. 2007, Vol. 9, No. 17,

Kobayashi, Chem.sAsian J. 2010, 5, 1974 Friedel-Crafts-type Reaction 52

conclusion 1. The Alkaline earth metals can be used in Many important reactions. But some of the mechanisms are unclear, still. Their positive use as catalysts in asymmetric synthesis is limited, also. 2. Their strong Bronsted basicity and mild Lewis acidity can influence their catalytic activity, as well as chiral modification of a complex in a positive manner. So synthesis of new ligands need to be considered. 53

Thank you for your attention! 54