Hydroboration and reductive amination of ketones and aldehydes with HBpin by a bench stable Pd(ii)-catalyst

Mahato, Shreya and Rawal, Parveen and Panda, Tarun K and et al, . (2022) Hydroboration and reductive amination of ketones and aldehydes with HBpin by a bench stable Pd(ii)-catalyst. Organic & Biomolecular Chemistry, 20 (5). pp. 1103-1111. ISSN 1477-0520

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Abstract

A palladium(ii) complex [(κ4-{1,2-C6H4(NCH-C6H4O)2}Pd] (1) supported by a dianionic salen ligand [1,2-C6H4(NCH-C6H4O)2]2- (L) was synthesised and used as a molecular pre-catalyst in the hydroboration of aldehydes and ketones. The molecular structure of Pd(ii) complex 1 was established by single-crystal X-ray diffraction analysis. Complex 1 was tested as a competent pre-catalyst in the hydroboration of aldehydes and ketones with pinacolborane (HBpin) to produce corresponding boronate esters in excellent yields at ambient temperature under solvent-free conditions. Further, the complex 1 proved to be a competent catalyst in the reductive amination of aldehydes with HBpin and primary amines under mild and solvent-free conditions to afford a high yield (up to 97%) of corresponding secondary amines. Both protocols provided high conversion, superior selectivity and broad substrate scope, from electron-withdrawing to electron-donating and heterocyclic substitutions. A computational study based on density functional theory (DFT) revealed a reaction mechanism for Pd-catalysed hydroboration of carbonyl species in the presence of HBpin. The protocols also uncovered the dual role of HBpin in achieving the hydroboration reaction. © 2022 The Royal Society of Chemistry.

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IITH Creators:

IITH Creators	ORCiD
Panda, Tarun K	http://orcid.org/0000-0003-0975-0118

Item Type:

Article

Additional Information:

BB sincerely thanks the Science and Engineering Research Board (SERB), India, for financial support under the EMPOWERMENT & EQUITY OPPORTUNITIES FOR EXCELLENCE IN SCIENCE (EEQ/2020/000079). SM is grateful to the Govt. of West Bengal for the Swami Vivekananda fellowship. TKP thanks the Indian Institute of Technology Hyderabad (IITH) for financial and instrumental support. DAK thanks University Grants Commission (UGC) India for his Ph. D. fellowship. PR thanks CSIR for the SRF fellowship (09/143 (1001)/2019-EMR-I). PG acknowledges SERB (CRG/2021/ 000759) for financial support. Computational facilities to PG were provided by IIT Roorkee. We also thank reviewers for their valuable suggestions to improve the manuscript.

Uncontrolled Keywords:

Complex 1; Hydroboration; Palladium complexes; Pd complex; Precatalysts; Reductive amination; Salen ligands; Solvent free conditions; Synthesised; ]+ catalyst

Subjects:

Chemistry
Chemical Engineering

Divisions:

Department of Chemistry

Depositing User:

. LibTrainee 2021

Date Deposited:

13 Jul 2022 12:17

Last Modified:

13 Jul 2022 12:17

URI:

http://raiithold.iith.ac.in/id/eprint/9655