CAN catalyst in Organic Chemistry

1. CERIUM(IV) AMMONIUM NITRATE AS A CATALYST IN ORGANIC SYNTHESIS Prepared By:- MOHD UMAR KHAN En. No. GD 5010 Roll No. 6020097

2. CONTENTS INTRODUCTION MECHANISTIC PATHWAYS APPLICATIONS CONCLUSION REFERENCES

3. INTRODUCTION Commercially available , use as one-electron oxidants Low toxicity , inexpensive R easonably soluble in many organic media Air- stable, easily handled, experimental simplicity Current goal is use of catalytic amounts of CAN Superior to manganese triacetate for the generation of radicals

4. MECHANISTIC PATHWAYS Various pathways are involved and different intermediates are formed Generation of radical and radical- cation species Reduction of Ce (IV) to Ce (III) Concomitant regeneration of Ce(IV) by an external oxidant Lewis acid catalysis

5. APPLICATIONS ( A) OXIDATION OF ALCOHOLS oxidation of some primary or secondary benzylic alcohols to the corresponding aldehydes or ketones in the presence of the NaBrO 3

6. The yield of the reactions is highly improved

7. the aerobic catalytic oxidation of benzylic and allylic alcohols using a catalytic system composed of can and 2,2,6,6-tetramethylpiperidinyl-1-oxyl ( tempo ) M ilder conditions and in shorter time with efficient yields

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9. (B)OXIDATION OF ACTIVE METHYLENE COMPOUNDS Direct transformation of diethyl malonate into diethyl ketomalonate by molecular oxygen O ptimal reaction conditions involved bubbling oxygen through a solution of the reactants in acetic acid-acetonitrile

10. MECHANISM

11. (C) Reactions Involving the Generation of Carbon-Carbon Bonds Most essential maneuver in synthetic organic chemistry. The CAN- induced generation of C-C bonds has been for some time an important aspect of the synthetic application of Ce (IV) species (a) Allylation of carbonyl compounds with allyltrimethylsilane:-

12. (d) Allylation of 1,3-dioxo compounds 1,3-Diketones, such as diethyl malonate, can also be converted to the corresponding monoallylated products in 74–98 % yields under the same conditions

13. (E)Removal of protecting gr oups An efficient reagent for removal of commonly used protecting groups Markó et al. applied CAN as a catalyst in the deprotection of acetals to give the parent ketones

14. (F) Synthesis of Benzothiazoles CAN catalyzes the reaction between o- mercaptoaniline and aromatic aldehydes at room temperature to give 2-arylbenzothiazoles The mechanism of this transformation involves CAN acting both as a Lewis acid and as an oxidant

15. MECHANISM

16. CONCLUSION Excellent, multipurpose catalyst that can be used to promote a wide range of synthetically relevant reactions that go well beyond its traditional role as an oxidant The reactions are characterized by their experimental simplicity and mild reaction conditions. Reactions may proceed via processes initiated by a one-electron oxidation, or alternatively CAN may act as a Brønsted acid catalyst, or as a Lewis acid Low cost and air stability of CAN may make it a useful alternative to the expensive

17. REFERENCES Ho, T. L. Synthesis 1978, 936. Kim, S. S.; Jung, H. C. Synthesis 2003, 2135 Ho, T. L. Synth. Commun . 1979, 9, 237. Zeng, X.-F.; Ji , S.J.; Wang, S.-Y. Tetrahedron 2005, 61, 10235. Aggarwal, V. K.; Vennall, G. P. Synthesiett . 2009, 19, 4501. Al - Qalaf, F.; Mekheimer, R. A.; Sadek, K. U. Molecules 2008, 13, 2908. More, S. V.; Sastry, M. N. V.; Yao, C.-F. s 1998, 1822. Sujatha , K.; Shanthi , G.; Selvam , N. P.; Manohara , S.; Perumal , P. T.; Rajendran , M. Bioorg . Med. Chem. L Green Chem. 2006, 8, 91. Shaabani, A.; Maleki, A. Chem. Pharm. Bull. 2008, 56, 79

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