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Synfacts 2012; 8(5): 0569
DOI: 10.1055/s-0031-1290933
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Polymeric Imidazole Pd Catalyst for Cross-Couplings

Contributor(s):
Yasuhiro Uozumi
,
Yoichi M. A. Yamada
,
Shaheen M. Sarkar
Yamada YM. A, * Sarkar SM, Uozumi Y. * RIKEN Advanced Science Institute, Wako, Institute for Molecular Science and The Graduate School for Advanced Studies, Okazaki, Japan
Self-Assembled Poly(imidazole-palladium): Highly Active, Reusable Catalyst at Parts per Million to Parts per Billion Levels.

J. Am. Chem. Soc. 2012;
134: 3190-3198
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Further Information

Publication History

Publication Date:
18 April 2012 (online)

 
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Key words

allylic arylation - amphiphilic imidazole polymers - heterogeneous palladium catalysis - Suzuki–Miyaura coupling

Significance

A self-assembled polymeric palladium catalyst MEPI-Pd 3 was prepared via the molecular convolution of (NH4)2PdCl4 and poly[(N-vinylimidazole)-co-(N-isopropylacrylamide)5]. MEPI-Pd 3 (0.8–40 mol ppm Pd) promoted the allylic ­arylation/alkenylation of allylic esters 4 with aryl/­alkenylboron reagents 5 in water and/or alcohol to give the corresponding products 6. MEPI-Pd 3 (0.28 mol ppm–0.1 mol% Pd) drove the ­Suzuki–Miyaura coupling of a variety of aryl chlorides, bromides, and iodides in water to give the corresponding biaryls 7.


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Comment

MEPI-Pd 3 was reused without loss of catalytic activity for the allylic arylation and the Suzuki–Miyaura coupling. MEPI-Pd with 0.28 mol ppm Pd efficiently promoted the Suzuki–Miyaura coupling of iodotoluene and phenylboronic acid to afford 7b quantitatively with a TON of 3,570,000 and a TOF of 119,000 h–1. The authors reported a preliminary communication for the allylic arylation of allylic acetates (Angew. Chem. Int. Ed. 2011, 50, 9437; Synfacts 2011, 1380).


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