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Stamoulis AG, Geng P, Schmidt MA, Eastgate MD, Borovika A, Fraunhoffer KJ, Stahl SS. Sustainable Pd(OAc)
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/Hydroquinone Cocatalyst System for
Cis
‐Selective Dibenzoyloxylation of 1,3‐Cyclohexadiene. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Peng Geng
- Chemical Process Development Bristol-Myers Squibb New Brunswick New Jersey 08903 USA
| | - Michael A. Schmidt
- Chemical Process Development Bristol-Myers Squibb New Brunswick New Jersey 08903 USA
| | - Martin D. Eastgate
- Chemical Process Development Bristol-Myers Squibb New Brunswick New Jersey 08903 USA
| | - Alina Borovika
- Chemical Process Development Bristol-Myers Squibb New Brunswick New Jersey 08903 USA
| | | | - Shannon S. Stahl
- Department of Chemistry University of Wisconsin-Madison Madison WI 53706 USA
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Stamoulis AG, Geng P, Schmidt MA, Eastgate MD, Borovika A, Fraunhoffer KJ, Stahl SS. Sustainable Pd(OAc) 2 /Hydroquinone Cocatalyst System for Cis-Selective Dibenzoyloxylation of 1,3-Cyclohexadiene. Angew Chem Int Ed Engl 2021; 60:23182-23186. [PMID: 34399005 DOI: 10.1002/anie.202108499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Indexed: 11/08/2022]
Abstract
The 1,4-diacyloxylation of 1,3-cyclohexadiene (CHD) affords valuable stereochemically defined scaffolds for natural product and pharmaceutical synthesis. Existing cis-selective diacyloxylation protocols require superstoichiometric quantities of benzoquinone (BQ) or MnO2 , which limit process sustainability and large-scale application. In this report, reaction development and mechanistic studies are described that overcome these limitations by pairing catalytic BQ with tert-butyl hydroperoxide as the stoichiometric oxidant. Catalytic quantities of bromide enable a switch from trans to cis diastereoselectivity. A catalyst with a 1:2 Pd:Br ratio supports high cis selectivity while retaining good rate and product yield. Further studies enable replacement of BQ with hydroquinone (HQ) as a source of cocatalyst, avoiding the handling of volatile and toxic BQ in large-scale applications.
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Affiliation(s)
- Alexios G Stamoulis
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Peng Geng
- Chemical Process Development, Bristol-Myers Squibb, New Brunswick, New Jersey, 08903, USA
| | - Michael A Schmidt
- Chemical Process Development, Bristol-Myers Squibb, New Brunswick, New Jersey, 08903, USA
| | - Martin D Eastgate
- Chemical Process Development, Bristol-Myers Squibb, New Brunswick, New Jersey, 08903, USA
| | - Alina Borovika
- Chemical Process Development, Bristol-Myers Squibb, New Brunswick, New Jersey, 08903, USA
| | - Kenneth J Fraunhoffer
- Chemical Process Development, Bristol-Myers Squibb, New Brunswick, New Jersey, 08903, USA
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
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