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Enantioselective synthesis of chiral sulfones by Rh-catalyzed asymmetric addition of boronic acids to alpha,beta-unsaturated 2-pyridyl sulfones.
J Org Chem. 2007 Dec 21; 72(26):9924-35.JO

Abstract

A general and efficient method for the rhodium-catalyzed enantioselective catalytic conjugate addition of organoboronic acids to alpha,beta-unsaturated sulfones is described. The success of the process relies on the use of alpha,beta-unsaturated 2-pyridyl sulfones as key metal-coordinating substrates; typical sulfones such as vinyl phenyl sulfones are inert under the reaction conditions. Among a variety of chiral ligands, Chiraphos provided the best asymmetric induction. This rhodium [Rh(acac)(C2H4)2]/Chiraphos catalyst system has a broad scope, being applicable to the addition of both aryl and alkenyl boronic acids to cis and trans alpha,beta-unsaturated 2-pyridyl sulfones. In most cases, especially in the addition of aryl boronic acids, the reactions take place cleanly and with high enantioselectivity, affording chiral beta-substituted 2-pyridyl sulfones in good yields and enantioselectivities (70-92% ee). The sense and magnitude of this enantioselectivity have been studied by DFT theoretical calculations of the aryl-rhodium insertion step. These calculations strongly support the formation of a five-membered pyridyl-rhodium chelated species as the most stable complex after the insertion into the C=C bond. These highly enantioenriched chiral sulfones are very appealing building blocks in enantioselective synthesis. For instance, the straightforward elimination of the 2-pyridylsulfonyl group by either Julia-Kociensky olefination or alkylation/desulfonylation sequences provides a variety of functionalized chiral compounds, such as allylic substituted alkenes or beta-substituted ketones and esters.

Authors+Show Affiliations

Departamento de Química OrgAnica, Facultad de Ciencias. Universidad Autónoma de Madrid, 28049 Madrid, Spain.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18047369

Citation

Mauleón, Pablo, et al. "Enantioselective Synthesis of Chiral Sulfones By Rh-catalyzed Asymmetric Addition of Boronic Acids to Alpha,beta-unsaturated 2-pyridyl Sulfones." The Journal of Organic Chemistry, vol. 72, no. 26, 2007, pp. 9924-35.
Mauleón P, Alonso I, Rivero MR, et al. Enantioselective synthesis of chiral sulfones by Rh-catalyzed asymmetric addition of boronic acids to alpha,beta-unsaturated 2-pyridyl sulfones. J Org Chem. 2007;72(26):9924-35.
Mauleón, P., Alonso, I., Rivero, M. R., & Carretero, J. C. (2007). Enantioselective synthesis of chiral sulfones by Rh-catalyzed asymmetric addition of boronic acids to alpha,beta-unsaturated 2-pyridyl sulfones. The Journal of Organic Chemistry, 72(26), 9924-35.
Mauleón P, et al. Enantioselective Synthesis of Chiral Sulfones By Rh-catalyzed Asymmetric Addition of Boronic Acids to Alpha,beta-unsaturated 2-pyridyl Sulfones. J Org Chem. 2007 Dec 21;72(26):9924-35. PubMed PMID: 18047369.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Enantioselective synthesis of chiral sulfones by Rh-catalyzed asymmetric addition of boronic acids to alpha,beta-unsaturated 2-pyridyl sulfones. AU - Mauleón,Pablo, AU - Alonso,Inés, AU - Rivero,Marta Rodríguez, AU - Carretero,Juan C, Y1 - 2007/11/30/ PY - 2007/12/1/pubmed PY - 2008/3/26/medline PY - 2007/12/1/entrez SP - 9924 EP - 35 JF - The Journal of organic chemistry JO - J Org Chem VL - 72 IS - 26 N2 - A general and efficient method for the rhodium-catalyzed enantioselective catalytic conjugate addition of organoboronic acids to alpha,beta-unsaturated sulfones is described. The success of the process relies on the use of alpha,beta-unsaturated 2-pyridyl sulfones as key metal-coordinating substrates; typical sulfones such as vinyl phenyl sulfones are inert under the reaction conditions. Among a variety of chiral ligands, Chiraphos provided the best asymmetric induction. This rhodium [Rh(acac)(C2H4)2]/Chiraphos catalyst system has a broad scope, being applicable to the addition of both aryl and alkenyl boronic acids to cis and trans alpha,beta-unsaturated 2-pyridyl sulfones. In most cases, especially in the addition of aryl boronic acids, the reactions take place cleanly and with high enantioselectivity, affording chiral beta-substituted 2-pyridyl sulfones in good yields and enantioselectivities (70-92% ee). The sense and magnitude of this enantioselectivity have been studied by DFT theoretical calculations of the aryl-rhodium insertion step. These calculations strongly support the formation of a five-membered pyridyl-rhodium chelated species as the most stable complex after the insertion into the C=C bond. These highly enantioenriched chiral sulfones are very appealing building blocks in enantioselective synthesis. For instance, the straightforward elimination of the 2-pyridylsulfonyl group by either Julia-Kociensky olefination or alkylation/desulfonylation sequences provides a variety of functionalized chiral compounds, such as allylic substituted alkenes or beta-substituted ketones and esters. SN - 0022-3263 UR - https://www.unboundmedicine.com/medline/citation/18047369/Enantioselective_synthesis_of_chiral_sulfones_by_Rh_catalyzed_asymmetric_addition_of_boronic_acids_to_alphabeta_unsaturated_2_pyridyl_sulfones_ L2 - https://doi.org/10.1021/jo7016197 DB - PRIME DP - Unbound Medicine ER -