ENZYME-CATALYZED REACTIONS Assoc . Prof. Dr. Devrim Özdemirhan

1. ENZYME-CATALYZED REACTIONSAssoc. Prof. Dr. Devrim Özdemirhan

2. Spirocyclic compounds found in the structure of natural products that have biological activities. The structures contain cyclopentenone-pyran ring composed of cyclopentenone ring known as cyclopentenone PG’s (prostaglandins) which are used in the treatment of many psychological desease. Dihydropyran ring containing compounds found in the structure of molecules used in the anti-cancer treatment drugs. Pauson-Khand Reaction (PKR) and Ring Closing Methatesis (RCM) are frequently used methods in the literature for the synthesis of spiro-cyclic units. Chiral tertiary alcohols are valuablebuilding blocks for these spiro-cyclic units

3. Spirocyclic compounds that will be synthesized

4. Retrosynthetic analysis of synthesis of spiro cyclopentenone-pyran and -furan compounds

5. Retrosynthetic analysis of synthesis of spiro -dihyropyran and -dihydrofuran compounds

6. Enzyme-catalyzed resolution ofallylic, homoallyl and homopropargyl tertiary alcohols

7. The construction of building blocks that contain chiral tertiary alcohol moieties has great importance in the field of natural product synthesis and pharmaceuticals It has been reported that various hydrolases PLE (Pig liver esterase), PPL (Porcine pancreatic lipase), CRL (Candida rugosa lipase) and CAL-A (Lipase A from Candida antarctica) are active biocatalysts toward tertiary alcohols and corresponding esters.

8. Conversion 35% E =65 CAL-A catalyzed kinetic resolution of (±)-2-phenylbut-3-yn-2-ol with vinyl acetate as acyl donor. S. Hari Krishna, M. Persson, U.T. Bornscheuer, Tetrahedron: Asymmetry, 2002, 13, 2693-2696

9. PLE-catalyzed enantioselective hydrolysis of (±)-3-ethynyl-3-oxbutyryl quinuclidine F. Coope, B. G. Main, Tetrahedron: Asymmetry, 1995, 6,1393-1398

10. Transesterification of (±)-1-methyl-2,3-dihydro-1H-inden-1-ol 1a and (±)-1-methyl-1,2,3,4 tetrahydro napthalen-1-ol 1b rac-1a-b (S)-(+)- 1a-b (S)-(+)-2a (S)-(-)-2a-b 1a;n=1 2a; n=1 1b; n=2 2b; n=2 Özdemirhan D., Sezer S., Sönmez Y., Tetrahedron:Asymmetry 19(2008) 2717-2720

11. Transesterification of these tertiary alcohols; CAL-A (Candida antarctica Lipase A) was found to be the best biocatalyst for 1b and CAL-A-CLEA (Lipase A, C. antarctica, cross-linked enzyme aggregate) for 1a, obtained with ee values of 20% and 45%, respectively, and the corresponding esters 2b and 2a with the ee values of 99% and 71%, respectively.

12. Enzyme-catalyzed resolution of allylic, homoallyl and homopropargyl tertiary alcohols

13. Optimization reactions done by (±)-1-allyl-cyclohex-2-en-1-ol By changing substrate/enzyme ratio (1:0.25 to 1:1) Various hydrolases CAL-A-CLEA, CRL, CAL-A, CAL-B and Amano PS-C II were tested. cosolvent ( i.e:THF, hexane, 1,4 dioxane, diisopropylether) temperature (25 to 32ºC)

14. The results of transesterification of (±) allylic, homoallyl and homopropargyl tertiary alcohols a Conversions were determined by HPLC analysis bEnantiomeric excesses were determined by Daicel Chiralcel OD-H and OJ-H column HPLC analysis

15. CONCLUSION • Enantioselective resolution of tertiary allylic, homoallyl and homopropargyl cyclopentenols and cyclohexenols were performed with high ee varying between 35 % and 90 % ee and corresponding esters up to 98 % ee by commercially available enzyme CAL-CLEA, between 30-32 ºC • The substituents on the quaternary center drastically influence the enantioselectivity of the enzyme • Temperature factor is crucial for high enantioselectivity

16. Pauson-Khand Reaction (PKR) and Ring Closing Methatesis (RCM) are frequently used methods in the literature for the construction of spiro-cyclic units. Pauson-Khand reaction is [2+2+1] cycloaddition reaction Proposed mechanism for Pauson-Khand reaction

17. Synthesis of fused tricyclic compounds have aromatic side chains PEREZ-SERRANO L., Blanco-Urgoiti J., Casarrubios L., Dominguez G., Perez-Castells J. P., Journal of Organic Chemistry (J. Org. Chem), 65, 11, 3513-19, (2000).

18. Retrosynthetic analysis of synthesis spiro cyclopentenone-pyran and - furan compounds

19. Synthesis of spiro cyclopentenone-pyran compounds by Pauson-Khand Reaction Synthesis of 4a',5'-dihydro-1'H- spiro[cyclopent[2]ene-1,3‘cyclopenta[c]pyran-6'(4'H)-one Synthesis of 7’,7a’-dihydro-2’H-spiro[cyclopent[2]ene-1,3’-[cyclopenta[b]pyran]-6’(4’H)-one

20. Synthesis of spiro cyclopentenone-furan compounds by Pauson-Khand Reaction Synthesis of 6’,6a’-dihydrospiro[cyclopent[2]en-1,1’cyclopenta[c]furan]-5’(3’H)-one

21. Synthesis of spiro cyclopentenone-pyran compounds by Pauson-Khand Reaction Synthesis of 4a’, 5’-dihydro-2’H-spiro[siklohex[2]ene-1,3’-cyclopenta[b]pyran]-6’(4’H)-one Synthesis of 7’,7a’-dihydro-2’H-spiro[siklohekz[2]en-1,3’-cylopenta[b]pyran 6’(4’H)-one

22. Synthesis of spiro cyclopentenone-furan compounds by Pauson-Khand Reaction Synthesis of 6’,6a’-dihydrospiro[cyclohex[2]en-1,1’-cyclopenta[c]furan-5’(3’H)-one

23. Retrosynthetic analysis of synthesis of spiro –dihyropyran and -dihydrofuran compounds

24. General Survey to Metathesis • Ring-Closing Methatesis (RCM) • Cross Methatesis (CM) • Acyclic Dien Methatesis Polymerization (ADMEP) • Ring-Opening Methatesis Polymerization (ROMP) • Enyn Methatesis (EYN) • Ring-Opening Cross Methatesis (ROCM)

25. Various Methatesis reactions

26. Some typical Methatesis catalysts

27. Ring-Closing Metathesis is the most popular method in the natural product synthesis We can explain the success of Ring Closing Methathesis (RCM) by three ways Variety of functional groups Ability to make macrocyclization reactions Ability to use pre-molibyden and ruthenium catalysts that satisfy easy binding to unsaturated groups

28. General mechanism for Ring-Closing Methatesis

29. Ring-Closing Methathesis (RCM) can be an important step in the synthesis of natural products such as (-)-pentanomycin synthesized by using 1st generation Grubbs catalysts. Synthesis of (-)-pentanomycin by Ring Closing Methatesis

30. Retrosynthetic analysis of synthesis of spiro -dihyropyran and -dihydrofuran compounds

31. Synthesis of spiro- dihydofuran compounds by Ring Closing Methatesis Synthesis of 1-oxaspiro[4,4]nona-3,6-dien Synthesis of 1-oxaspiro[4,5]deca-3,6-dien

32. Synthesis of spiro -dihydropyran compounds by Ring Closing Methatesis Synthesis of 6-oxaspiro[4,5]deca-1,8-dien Synthesis of 1-oxaspiro[5,5]undeca-3,7-dien

33. Spiro-dihyropyran compounds 6-oxaspiro[4,5]deca-1,8-dien and 1-oxaspiro[5,5]undeca-3,7-dien were obtained by Ring Closing Metatesis reaction with high chemical yields 83 % and 89 % overall yield respectively,also spiro-dihydrofuran compounds 1-oxaspiro[4,4]nona-3,6-dien and 1-oxaspiro[4,5]deca-3,6-dien were obtained with 90 % and 93 % chemical yield respectively. CONCLUSION

34. Cylopentene based spiro cyclopentenone-pyran compounds 4a',5'-dihydro-1'H- spiro[cyclopent[2]ene-1,3‘cyclopenta[c]pyran-6'(4'H)-one and 7’,7a’-dihydro-2’H-spiro[cyclopent[2]ene-1,3’-[cyclopenta[b]pyran]-6’(4’H)-one were synthesized by Pauson-Khand Reaction with 87 % and 85 % chemical yields. In the same manner cyclohexene based spiro cyclopentenone-pyran compounds 4a’, 5’-dihydro-2’H-spiro[siklohex[2]ene-1,3’-cyclopenta[b]pyran]-6’(4’H)-one and 7’,7a’-dihydro-2’H-spiro[siklohekz[2]en-1,3’-cylopenta[b]pyran-6’(4’H)-one obtained by 87 % and 89 % chemical yield.

35. Spiro cyclopentenone-furan compounds, 6’,6a’- dihydrospiro[cyclopent[2]en-1,1’-cyclopenta[c]furan]-5’(3’H)-one and 6’,6a’-dihydrospiro[cyclohex[2]en-1,1’-cyclopenta[c]furan- 5’(3’H)-one were synthesized by Pauson-Khand Reaction obtained with 83 % and 79 % chemical yield respectively.

36. ACKNOWLEDGEMENTS • Prof. Dr. Cihangir Tanyeli • Msc. Ayça Güzel • Scientific and Technological Research Council of grant [TBAG-110T169]

37. THANKS FOR YOUR ATTENTION!