James Takacs

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James Takacs

Emeritus Professor Retirees University of Nebraska-Lincoln

Contact

Address
HAH 807B
Lincoln NE 68588-0304
Phone
402-472-3501 On-campus 2-3501
Email
jtakacs1@unl.edu

Education

  • Postdoctoral, Swiss National Funds International Postdoctoral Fellow, Swiss Federal Institute of Technology
  • Ph.D., California Institute of Technology
  • B.S., Rutgers University

Research Interests

Asymmetric Catalysis, Self-Assembly, Combinatorial Catalysis, Metal-Catalyzed Cyclizations, Synthetic Methods Development, Natural Product Total Synthesis

Current Research

Catalytic Asymmetric Hydroboration (CAHB) has been around for a long time, and many outstanding research groups have contributed to understanding this (fiendishly complex) catalyzed counterpart of the classic stoichiometric reaction.[i] Now, as new methods rapidly evolve using chiral secondary and tertiary boronic esters for stereospecific carbon-carbon bond construction,[ii] the development of new catalyst systems and the exploration of new substrates for CAHB are enjoying renewed interest. Recent work in the Takacs group has focused on developing the CAHB, mostly rhodium-catalyzed CAHBs, of substrates capable of two-point binding to the metal center. The observation of unusual Markovnikov regioselectivity leading to chiral tertiary boronic esters is among the important advances. For example, we recently published a simple, in situ-generated, chiral rhodium catalyst for which methylidene and trisubstituted alkene substrates form chiral tertiary boronic esters (up to 87% yield and 96:4 enantiomer ratio (er)) via oxime-directed CAHB. Subsequent C–C coupling is used to form a quaternary all carbon stereocenter, while other transformations lead to chiral diols, O-substituted hydroxylamines, and isoxazolines.[iii] Similarly, as illustrated below, phosphonate-derived CAHB affords new, bifunctional chiral tertiary boronic ester synthons suitable for further elaboration.[iv] Recently, it has been discovered that H2 will “hitch a ride” on the CAHB catalyst interrupting hydroboration to arrive at efficient Catalytic Asymmetric Hydrogenation (CAH).[v]

Figure 1

Takacs Research Group Homepage

Select Publications

[i] A. M. Carroll, T. P. O’Sullivan, P. J. Guiry, Adv. Synth. Catal., 2005, 347, 609–631; b) C. M. Crudden, D. Edwards, Eur. J. Org. Chem., 2003, 24, 4695–4712.

[ii] D. Leonori, V. K. Aggarwal, Angew. Chem. Int. Ed., 2014, 54, 1082-1096.

[iii] V. M. Shoba, N. C. Thacker, A. J. Bochat, J. M. Takacs, Angew. Chem. Int. Ed., 2016, 55, 1465–1469.

[iv] Suman Chakrabarty, James M. Takacs, J. Am. Chem. Soc., 2017, Article ASAP. DOI: 10.1021/jacs.7b02324.

[v] Veronika M. Shoba, James M. Takacs, J. Am. Chem. Soc., 2017, 139, 5740-5743.