TY - JOUR
T1 - Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes
AU - Lu, Yansong J.
AU - Zhang, Xiawei
AU - Malakar, Santanu
AU - Krogh-Jespersen, Karsten
AU - Hasanayn, Faraj
AU - Goldman, Alan S.
N1 - Funding Information:
We thank Zhuo Gao, Drs. Amlan Ray, Sabuj Kundu and Ritu Ahuja for generously providing samples of various catalysts. We gratefully acknowledge support by the National Science Foundation through grant CHE-1465203. The authors acknowledge the Office of Advanced Research Computing at Rutgers, The State University of New Jersey for providing access to the Amarel cluster and associated research computing resources.
Funding Information:
We thank Zhuo Gao, Drs. Amlan Ray, Sabuj Kundu, and Ritu Ahuja for generously providing samples of various catalysts. We gratefully acknowledge support by the National Science Foundation through grant CHE-1465203. The authors acknowledge the Office of Advanced Research Computing at Rutgers, The State University of New Jersey for providing access to the Amarel cluster and associated research computing resources.
PY - 2020/3/6
Y1 - 2020/3/6
N2 - Di-isopropylphosphino-substituted pincer-ligated iridium catalysts are found to be significantly more effective for the dehydrogenation of simple tertiary amines to give enamines than the previously reported di-t-butylphosphino-substituted species. It is also found that the di-isopropylphosphino-substituted complexes catalyze dehydrogenation of several β-functionalized tertiary amines to give the corresponding 1,2-difunctionalized olefins. The di-t-butylphosphino-substituted species are ineffective for such substrates; presumably, the marked difference is attributable to the lesser crowding of the di-isopropylphosphino-substituted catalysts. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α-C-H bond followed by rate-determining elimination of the β-C-H bond.
AB - Di-isopropylphosphino-substituted pincer-ligated iridium catalysts are found to be significantly more effective for the dehydrogenation of simple tertiary amines to give enamines than the previously reported di-t-butylphosphino-substituted species. It is also found that the di-isopropylphosphino-substituted complexes catalyze dehydrogenation of several β-functionalized tertiary amines to give the corresponding 1,2-difunctionalized olefins. The di-t-butylphosphino-substituted species are ineffective for such substrates; presumably, the marked difference is attributable to the lesser crowding of the di-isopropylphosphino-substituted catalysts. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α-C-H bond followed by rate-determining elimination of the β-C-H bond.
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U2 - 10.1021/acs.joc.9b02846
DO - 10.1021/acs.joc.9b02846
M3 - Article
C2 - 31990556
AN - SCOPUS:85081902787
VL - 85
SP - 3020
EP - 3028
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 5
ER -