This document discusses the selective hydrogenation of alkynes using a combination of carboxylic acids and group 10 transition metal complexes. Specifically: - The combination of carboxylic acids and group 10 transition metals like Pd(0) efficiently catalyzes transformations of alkynes, but the reaction mechanisms were unclear. - The objective is to achieve facile and stereoselective hydrometalation of alkynes, generating isolated alkenyl metal complexes. - Hydrometalation proceeds via the reaction of an alkyne-coordinated metal complex with the acid. This provides direct evidence for the involvement of carboxylic acid and zerovalent metals in the reaction mechanism. - Based on this

1. Facile Regio and Stereoselective Hydrometalation of Alkynes with a
Combination of Carboxylic Acids and Group 10 Transition Metal
Complexes: Selective Hydrogenation of Alkynes with Formic Acid
Presented by
Ashok Jangid
School of chemical sciences
Central university of Gujarat

2. Outline
Introduction
Objective
Reaction path
Importance of the study
Conclusion

3. Introduction
Conversion of alkynes to alkens can be achieved by hydrogenation
 Lindlars catalyst
 Raney nikel
 Pd/C
These methods are often suffers from the lack of chemo and stereoselectivity
Combination of Pd(0) complex with carboxylic acid is an efficient catalyst for various transformations of alkynes
 Cyclization of enynes
 Hydrocarbonylation
 Hydroarylation
 Cyclo isomerization of alkynes
For these reactions mechanistic aspects were not clear and a direct proof of formation of alkenyl Pd intermediate is not clear

4. Objectives
Facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex
Selective Hydrogenation of Alkynes with Formic Acid

5. Reaction path
Scheme 1:
Hydrometalation proceeds via a reaction of an alkyne coordinate metal (0) complex with the acid

6. Scheme 2 Reaction Path to Complex alkenyl Pt Complex

7. Scheme 3 Selective Hydrogenation of Alkynes with Formic Acid

8. Importance of the study
 Isolation of alkenyl Pd intermediate
 Characteristic property of group 10 transition metals
 By using formic acid selective hydrogenation of alkynes

9. Conclusion
Facile hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition
metal complexes M(PEt3)4 (M = Ni, Pd, Pt) to afford fully characterized alkenyl metals was
revealed. This finding provides direct proof for the reaction mechanism involving the combination
of carboxylic acid and zerovalent palladium catalyst. On the basis of this finding, an unprecedented
controllable hydrogenation of alkynes with formic acid was developed to selectively produce cis-,
trans-alkenes and alkanes by slightly tuning the conditions.

10. References
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11. For your kind attention !!!!!!!!!!!!!!!!!!