T. V. Rajan Babu

T.V. (Babu) RajanBabu is an organic chemist who holds the position of Distinguished Professor of Chemistry in the College of Arts and Sciences at the Ohio State University. His laboratory traditionally focuses on developing transition metal-catalyzed reactions. RajanBabu is known for helping develop the Nugent-RajanBabu reagent (Bis(cyclopentadienyl)titanium(III) chloride), a chemical reagent used in synthetic organic chemistry as a single electron reductant.[1]

T. V. (Babu) RajanBabu
Born
T. V. RajanBabu
Alma materOhio State University Ph.D (1977)
Known forOrganometallic chemistry, Organic chemistry
AwardsArthur C. Cope Scholar Award (2020)
Scientific career
FieldsChemistry
InstitutionsOhio State University
Doctoral advisorsHarold Shechter
Other academic advisorsRobert Burns Woodward
WebsiteFaculty Page

Education and professional experience

RajanBabu received his B. Sc (Special) from Kerala University in 1969 and M. Sc. degree from The Indian Institute of Technology (IIT, Madras) in 1971.  He obtained his Ph. D. from The Ohio State University in 1979 working with Professor Harold Shechter, and was a postdoctoral fellow at Harvard University with Professor R. B. Woodward from 1978 to 1979. Notable work during his postdoctoral career includes the total synthesis of erythromycin.[2] RajanBabu was a Member of Research Staff and Research Fellow at DuPont Central Research from 1980 to 1994 until joining the Ohio State University faculty as a Professor of Chemistry in 1995.[3]

Research

Research in the RajanBabu lab is focused on development of new methodology for stereoselective synthesis.[4] Major research areas include:

Asymmetric Hydrovinylation

RajanBabu developed methodology surrounding C-C bond formation via metal-catalyzed hydroformylation. They reported several asymmetric examples through the usage of chiral phosphine ligand with a hemilabile coordinating group.[5][6] This method was applicable using vinylarenes, 1,3-dienes[7] and strained olefins as substrates. Applications of this chemistry include a new synthesis of (S)-ibuprofen[8] and a new approach to controlling the exocyclic side-chain stereochemistry in helioporin D[9] and pseudopterocins.[10] Related to this methodology, RajanBabu also developed a tandem [2+2] cycloaddition/asymmetric hydrovinylation reaction to allow conversion of simple precursors (ethylene, enynes) to structurally complex cyclobutanes.[11]

Asymmetric Hydrocyanation

The RajanBabu group developed methodology in the area of hydrocyanation, leveraging the reaction of vinylarenes with HCN in the presence of Ni(0) complexes. Based on the phosphorus ligands within the Ni complex, the reaction can be rendered asymmetric.[12][13] The enantioselectivity could be further improved by tuning the electronics of the phosphine ligands to electronically differentiate the phosphorus chelates. Electronic tuning was accomplished, for example, using widely available sugars such as D-glucose and D-fructose.

Radical Epoxide Opening

For further information on the Nugent-RajanBabu reagent, please see Bis(cyclopentadienyl)titanium(III) chloride.

Multicomponent Cyclization

One area of interest to the RajanBabu group is catalytic multicomponent addition/cyclization reactions. This methodology allows for formation of carbocyclic and heterocyclic compounds from acyclic precursors including unactivated olefins and acetylenes.[14] This method leverages the reactivity of bifunctional reagents (X-Y) where X-Y in above scheme can represent R3Si−SiR‘3, R3Si−SnR‘3, R3Si−BR‘2, R3Sn−BR‘2, and trialkylsilicon- and trialkyltin- hydrides. The reactions are palladium-catalyzed, and incorporation of the X and Y species allows for vast diversification of the end products.[15][16][17] Application of this methodology afforded syntheses of highly alkylated indolizidines such as IND-223A.[18]

Additional Methods

RajanBabu has evaluated asymmetric aziridine openings with high enantioselectivity using yttrium- and lanthanide- salen complexes.[19] The RajanBabu group has also developed water-soluble Rhodium(I) complexes, allowing for reactions to be run in aqueous media.[20]

Publications

RajanBabu has over 160 publications to date and has co-authored several reviews and patents. His H-index is 56. [21]

Notable publications include:

  • Group-transfer polymerization. 1. A new concept for addition polymerization with organosilicon initiators[22]
  • Selective Generation of Free Radicals from Epoxides Using a Transition-Metal Radical. A Powerful New Tool for Organic Synthesis[23]
  • Transition-metal-centered radicals in organic synthesis. Titanium(III)-induced cyclization of epoxy olefins[24]
  • Ligand Electronic Effects in Asymmetric Catalysis: Enhanced Enantioselectivity in the Asymmetric Hydrocyanation of Vinylarenes[25]
  • Beyond Nature's Chiral Pool - Enantioselective Catalysis in Industry[26]

Honors

References
  1. RajanBabu, T. V.; Nugent, William A. (February 1994). "Selective Generation of Free Radicals from Epoxides Using a Transition-Metal Radical. A Powerful New Tool for Organic Synthesis". Journal of the American Chemical Society. 116 (3): 986–997. doi:10.1021/ja00082a021. ISSN 0002-7863.
  2. Woodward, R. B.; Logusch, E.; Nambiar, K. P.; Sakan, K.; Ward, D. E.; Au-Yeung, B. W.; Balaram, P.; Browne, L. J.; Card, P. J.; Chen, C. H. (1981). "Asymmetric total synthesis of erythromycin. 3. Total synthesis of erythromycin". Journal of the American Chemical Society. 103 (11): 3215–3217. doi:10.1021/ja00401a051. ISSN 0002-7863.
  3. "T. V. Rajanbabu – The RajanBabu Group". research.cbc.osu.edu. Retrieved 2021-06-12.
  4. "Perspectives – The RajanBabu Group". research.cbc.osu.edu. Retrieved 2021-06-12.
  5. Nomura, Nobuyoshi; Jin, Jian; Park, Haengsoon; RajanBabu, T. V. (1998). "The Hydrovinylation Reaction: A New Highly Selective Protocol Amenable to Asymmetric Catalysis". Journal of the American Chemical Society. 120 (2): 459–460. doi:10.1021/ja973548n. ISSN 0002-7863.
  6. Smith, Craig R.; RajanBabu, T. V. (2008-04-01). "Efficient, Selective, and Green: Catalyst Tuning for Highly Enantioselective Reactions of Ethylene". Organic Letters. 10 (8): 1657–1659. doi:10.1021/ol800395m. ISSN 1523-7060. PMC 2746057. PMID 18351772.
  7. Sharma, Rakesh K.; RajanBabu, T. V. (2010-03-17). "Asymmetric Hydrovinylation of Unactivated Linear 1,3-Dienes". Journal of the American Chemical Society. 132 (10): 3295–3297. doi:10.1021/ja1004703. ISSN 0002-7863. PMC 2836389. PMID 20163120.
  8. Smith, Craig R.; RajanBabu, T. V. (2009-04-17). "Catalytic Asymmetric Synthesis Using Feedstocks: An Enantioselective Route to 2-Arylpropionic Acids and 1-Arylethyl Amines via Hydrovinylation of Vinyl Arenes". The Journal of Organic Chemistry. 74 (8): 3066–3072. doi:10.1021/jo900198b. ISSN 0022-3263. PMC 2748116. PMID 19317393.
  9. Tenneti, Srinivasarao; Biswas, Souvagya; Cox, Glen Adam; Mans, Daniel J.; Lim, Hwan Jung; RajanBabu, T. V. (2018-08-08). "Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control". Journal of the American Chemical Society. 140 (31): 9868–9881. doi:10.1021/jacs.8b03549. ISSN 0002-7863. PMC 6082684. PMID 30001133.
  10. Mans, Daniel J.; Cox, G. Adam; RajanBabu, T. V. (2011-04-20). "Ethylene in Organic Synthesis. Repetitive Hydrovinylation of Alkenes for Highly Enantioselective Syntheses of Pseudopterosins". Journal of the American Chemical Society. 133 (15): 5776–5779. doi:10.1021/ja201321v. ISSN 0002-7863. PMC 3087302. PMID 21449569.
  11. Pagar, Vinayak Vishnu; RajanBabu, T. V. (2018-07-06). "Tandem catalysis for asymmetric coupling of ethylene and enynes to functionalized cyclobutanes". Science. 361 (6397): 68–72. Bibcode:2018Sci...361...68P. doi:10.1126/science.aat6205. ISSN 0036-8075. PMC 6055924. PMID 29976822.
  12. RajanBabu, T. V.; Casalnuovo, Albert L. (1992). "Tailored ligands for asymmetric catalysis: the hydrocyanation of vinyl arenes". Journal of the American Chemical Society. 114 (15): 6265–6266. doi:10.1021/ja00041a066. ISSN 0002-7863.
  13. Casalnuovo, Albert L.; RajanBabu, T. V.; Ayers, Timothy A.; Warren, Timothy H. (1994). "Ligand Electronic Effects in Asymmetric Catalysis: Enhanced Enantioselectivity in the Asymmetric Hydrocyanation of Vinylarenes". Journal of the American Chemical Society. 116 (22): 9869–9882. doi:10.1021/ja00101a007. ISSN 0002-7863.
  14. Radetich, Branko; RajanBabu, T. V. (1998). "Catalyzed Cyclization of α,ω-Dienes: A Versatile Protocol for the Synthesis of Functionalized Carbocyclic and Heterocyclic Compounds". Journal of the American Chemical Society. 120 (31): 8007–8008. doi:10.1021/ja9738788. ISSN 0002-7863.
  15. Shin, Seunghoon; RajanBabu, T. V. (2001). "Regio- and Stereochemical Control in Bis-functionalization−Cyclization: Use of Alleneyne Precursors for Carbocyclic and Heterocyclic Synthesis". Journal of the American Chemical Society. 123 (34): 8416–8417. doi:10.1021/ja011281t. ISSN 0002-7863. PMID 11516299.
  16. Chenard, B. L.; Laganis, E. D.; Davidson, F.; RajanBabu, T. V. (1985). "Silyl stannanes: useful reagents for bis-functionalization of .alpha.,.beta.-unsaturated ketones and acetylenes". The Journal of Organic Chemistry. 50 (19): 3666–3667. doi:10.1021/jo00219a058. ISSN 0022-3263.
  17. Gréau, Sandra; Radetich, Branko; RajanBabu, T. V. (2000-09-01). "First Demonstration of Helical Chirality in 1,4-Disubstituted ( Z,Z )-1,3-Dienes: R 3 Si−SnR' 3 -Mediated Cyclization of 1,6-Diynes". Journal of the American Chemical Society. 122 (35): 8579–8580. doi:10.1021/ja0015500. ISSN 0002-7863.
  18. Kumareswaran, Ramaiah; Gallucci, Judith; RajanBabu, T. V. (2004). "Tuning the Acceptors in Catalyzed Cyclizations Initiated by Allenes. Silylstannylation/Cyclization of Allene-Aldehydes for Synthesis of Polyalkylated Indolizidines Including 223A Congeners". The Journal of Organic Chemistry. 69 (26): 9151–9158. doi:10.1021/jo048580w. ISSN 0022-3263. PMID 15609949.
  19. Wu, Bin; Gallucci, Judith C.; Parquette, Jon R.; RajanBabu, T. V. (2014). "Bimetallic catalysis in the highly enantioselective ring–opening reactions of aziridines". Chem. Sci. 5 (3): 1102–1117. doi:10.1039/C3SC52929K. ISSN 2041-6520.
  20. RajanBabu, T. V.; Yan, Yuan-Yong; Shin, Seunghoon (2001). "Synthesis, Characterization, and Applicability of Neutral Polyhydroxy Phospholane Derivatives and Their Rhodium(I) Complexes for Reactions in Organic and Aqueous Media". Journal of the American Chemical Society. 123 (42): 10207–10213. doi:10.1021/ja011500a. ISSN 0002-7863. PMID 11603970.
  21. "Web of Science | Clarivate Analytics". app.webofknowledge.com. Retrieved 2021-06-12.
  22. Webster, O. W.; Hertler, W. R.; Sogah, D. Y.; Farnham, W. B.; RajanBabu, T. V. (1983). "Group-transfer polymerization. 1. A new concept for addition polymerization with organosilicon initiators". Journal of the American Chemical Society. 105 (17): 5706–5708. doi:10.1021/ja00355a039. ISSN 0002-7863.
  23. RajanBabu, T. V.; Nugent, William A. (1994). "Selective Generation of Free Radicals from Epoxides Using a Transition-Metal Radical. A Powerful New Tool for Organic Synthesis". Journal of the American Chemical Society. 116 (3): 986–997. doi:10.1021/ja00082a021. ISSN 0002-7863.
  24. Nugent, William A.; RajanBabu, T. V. (1988). "Transition-metal-centered radicals in organic synthesis. Titanium(III)-induced cyclization of epoxy olefins". Journal of the American Chemical Society. 110 (25): 8561–8562. doi:10.1021/ja00233a051. ISSN 0002-7863.
  25. Casalnuovo, Albert L.; RajanBabu, T. V.; Ayers, Timothy A.; Warren, Timothy H. (1994). "Ligand Electronic Effects in Asymmetric Catalysis: Enhanced Enantioselectivity in the Asymmetric Hydrocyanation of Vinylarenes". Journal of the American Chemical Society. 116 (22): 9869–9882. doi:10.1021/ja00101a007. ISSN 0002-7863.
  26. Nugent, W. A.; RajanBabu, T. V.; Burk, M. J. (1993-01-22). "Beyond Nature's Chiral Pool: Enantioselective Catalysis in Industry". Science. 259 (5094): 479–483. Bibcode:1993Sci...259..479N. doi:10.1126/science.259.5094.479. ISSN 0036-8075. PMID 17734166. S2CID 38641312.
  27. Wang, Linda (January 10, 2020). "2020 Cope and Cope Scholar Award winners Recipients are honored for contributions of major significance to chemistry". Chemical & Engineering News. Vol. 98, no. 2. ISSN 0009-2347. Retrieved 9 April 2022.
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