John A. Soderquist

Professor

Phone: 787-751-7779
Fax: 787-751-7779
Email: jas@janice.uprrp.edu

Education

Ph.D., University of Colorado, 1977.
Postdoctoral, Purdue University, 1977-1979.

Research Interests

Organic Organometallic Chemistry: Organometallic Reagents in Organic Synthesis and Natural Product Chemistry; Stereochemically Defined Functional Derivatives of Main Group Organometallics; Silicon-Containing Analogues of Natural Products; Metal-Metalloid Combinations for Organic Synthesis.

Research Focus

We are interested in the invention and development of new asymmetric reagents and catalysts derived from organometallic derivatives of Main Group elements such as boron and silicon. We are also interested in the design and total synthesis of natural products and pharmaceuticals through the use of these novel reagents and catalysts. Much of our efforts in this regard have been directed toward the use of bulky silicon groups to influence the chemistry of organoborane processes in synthetically useful ways.

Our research in the chemistry of organoboranes has centered around the use of the particularly stable 9-borabicyclo[3.3.1nonane (9-BBN) ring system. We have discovered numerous applications of this boron ligation for the important Pd-catalyzed cross coupling process termed the "Suzuki-Miyaura Coupling" including new enantioselective routes to frontalin and exobrevicomin. We have found that by substituting the hydrogen of an acetylene with a trialkylsilyl group, its monohydroboration with 9-BBN-H could be markedly enhanced thereby providing stereodefined silylated vinylboranes efficiently which function as highly effective partners for the Suzuki-Miyaura coupling. This led us to develop novel all-boron routes to such important pharmaceuticals as ibuprofen and naproxen. We also discovered that with the simple mono-oxidation of 9-BBN derivatives, the resulting air-stable borinate esters, that is the 10-bora-9-oxabicyclo[3.3.2]decane (OBBD) system. The B-substituted OBBDs are extremely convenient to use in the coupling process matching the excellent efficiencies achieved with 9-BBN derivatives while being much easier to handle. Of particular significance is the ease of methylation or silylmethylation which can be achieved with these reagents. We have also developed novel routes to cis, trans, and Markovnikov vinylboranes which we have used in this coupling. Moreover, we also developed a new way to utilize 9-BBN derivatives in the coupling process which avoids having to isolate these intermediates when they are generated through organometallic processes. For example, the addition of alkynyllithiums to 9-MeO-9-BBN produces an intermediate methoxyborate complex which is directly coupled to electrophilic substrates without added base or requiring the isolation of the organoborane, a particularly difficult task in these cases. This breakthrough made possible the simple synthesis of substituted acetylenes with alkynylboranes for the first time. After a thorough mechanistic study of the coupling process, have also utilized these findings in novel cyclopropylation process.

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The triisopropylsilyl (TIPS) group has also played a central role in our discovery of new ways to block reactive sites on protic functionality to conduct selected transformations. For example the silanethiol, (TIPS)SH provides a highly effective reagent for the synthesis of mercaptans, unsymmetrical sulfides and thiono esters, while its oxygen counterpart, TIPSOH, is a particularly effective new phase-transfer catalyst for dehydrohalogenation. The novel TIPS hydrazine not only protects aldehydes and ketones from organometallic reagents, but also provides a useful way to prepare unsymmetrical azines. We also utilized the stabilizing properties of the TIPS group to prepare a stable formylsilane viewing its chemistry as a highly unusual unsymmetrical form of formaldehyde.

Selected Recent Publications

119.     Enantiomerically Pure α-Amino Aldehydes  from Triisopropylsilylated α-Amino Acids,  Soto-Cairoli, B.; Justo de Pomar, J.; Soderquist, J. A. Org. Lett., 2008, 10, 333. DOI: 10.1021/ol7028993

120.    Diborane, First Update, Soderquist, J. A.; Matos, K., e-EROS Encyclopedia of Reagents for Organic Synthesis, J. Wiley & sons, New York, in press.

121.    9-Borabicyclo[3.3.2]decanes and the Asymmetric Hydroboration of 1,1-Disubstituted Alkenes, Gonzalez, A. Z.; Román, J. G.; Gonzalez, E.; Martinez, J.; Medina, J. R.; Matos, K.; Soderquist, J. A. J. Am.  Chem.  Soc., 2008, 130, 9218. DOI: 10.1021/ja803119p

122.    (+)-9-(1S,2S-Pseudoephedrinyl)-(10R)-(trimethylsilyl)-9-borabicyclo[3.3.2]decane, Soderquist, J. A., e-EROS Encyclopedia of Reagents for Organic Synthesis, J. Wiley & sons, New York, in press.

123.    (+)-(1S,2S)-N-Methylpseudoephedrinyl)-(10S)-phenyl-9-borabicyclo[3.3.2]decane, Soderquist, J. A., e-EROS Encyclopedia of Reagents for Organic Synthesis, J. Wiley & sons, New York, in press.

124.    Borabicyclo[3.3.2]decanes and the Stereoselective Asymmetric Synthesis of 1,3-Diol Stereotriads from 1,3-Diborylpropenes, González, A. Z.; Román, J. G.;  Alicea, E.; Canales, E.; Soderquist, J. A. J. Am.  Chem.  Soc., 2009, 131, 1269. DOI: 10.1021/ja808360z

125.    Strict Reagent Control in the Asymmetric Allylboration of N-TIPS-α-Amino Aldehydes with the B-Allyl-10-TMS-9-borabicyclo[3.3.2]decanes,  Soto-Cairoli, B.; Soderquist, J. A. Org. Lett., 2009, 11, 401. DOI: 10.1021/ol802685e

126.    Synthesis of 1-Stannacyclopent-3-enes and Their Pyrolysis to Stannylenes, Zhou, D.; Reiche, C.; Nag, M.; Soderquist, J. A.; Gaspar, P. P. Organometallics, 2009, 28, 2595. DOI: 10.1021/om800541f

127.    Asymmetric γ-Methoxyallylation with the Robust 10-TMS-9-borabicyclo[3.3.2]-decanes, Muňoz-Hernández, L.; Soderquist, J. A. Org. Lett., 2009, 11, 2571. DOI: 10.1021/ol900865y

128.    (E)-2-Boryl-1,3-butadiene Derivatives of the 10-TMS-9-BBDs: Highly Selective Reagents for the Asymmetric Synthesis of anti-1,2-Disubstituted-3,4-pentadien-1-ols, González, J. R.; González, A. Z.; Soderquist, J. A. J. Am.  Chem.  Soc. 2009, 131, 9924. DOI: 10.1021/ja9047202.

129.    Selective Triisopropylsilylation of -Amino Acids: Protection without Racemization, Soto-Cairoli, B.; Kock, I.; Justo de Pomar, J.; Yang, G.; Guzmán, J. M.; González, J. R.; Antomattei, A.; Soderquist, J. A. Hetereocycles 2010, 80, ASAP. DOI: 10.3987/COM-09-S(S)37 Published on the Web, August 11, 2009.