Catalytic Activity and Reaction Mechanism of FLPs for the Reduction of Enamine

doi:10.7503/cjcu20220555

Abstract

Abstract:

Over the decade after the pioneering work of frustrated Lewis pair（FLP） chemistry， this research area has achieved tremendous success as novel transition-metal-free system in organic synthesis， enzymatic models， and material sciences. The popularly accepted mechanism of FLP reactivity involves the polarization and heterolytic cleavages of a substrate molecular. Whiles there are also few work showing differing reaction mechanisms for special kinds of Frustrated radical pairs（FRPs）， which suggests a homolytic cleavage via one-electron processes. This work studied the Si—H bond activation by B（C₆F₅）₃ and enamines. In the presence of B（C₆F₅）₃ enamines did not undergo the expected hydrosilyation with silanes. The dominated hydrogenation products could not match the classic heterolytic cleavages mechanism by B（C₆F₅）₃ activating R₃Si—H and transferring of R₃Si⁺ to a nucleophile. The isotopic experiment results supported a mechanism that proceeds via the highly reactive radical anion［B（C₆F₅）₃］^- as the reported FRP behaviors. Understanding the reaction mechanisms is not only crucial to progress in fundamental chemical research but also for further broadens the potential reactivity of FLP systems.

Key words: Frustrated Lewis pair, Enamine, Reduction, Mechanism, Frustrated radical pair

CLC Number:

O621.2

TrendMD:

WEN Zhiguo, QIAO Zaiyin, TIAN Chong, MAXIM Borzov, NIE Wanli. Catalytic Activity and Reaction Mechanism of FLPs for the Reduction of Enamine[J]. Chem. J. Chinese Universities, 2022, 43(11): 20220555.

Figures/Tables 10

References 23

1	Welch G. C.， Juan R. R. S.， Masuda J. D.， Stephan D. W.， Science， 2006， 314（5802）， 1124—1126
2	Welch G. C.， Stephan D. W.， J. Am. Chem. Soc.， 2007， 129（7）， 1880—1881
3	Sumerin V.， Schulz F.， Nieger M.， Leskelä M.， Repo T.， Rieger B.， Angew Chem. Int. Ed.， 2008， 47（32）， 6001—6003
4	Chen D.， Wang Y.， Klankermayer J.， Angew. Chem. Int. Ed.， 2010， 49（49）， 9475—9478
5	Stephan D. W.， Erker G.， Angew. Chem. Int. Ed.， 2010， 49（1）， 46—76
6	Mahdi T.， Stephan D. W.， J. Am. Chem. Soc.， 2014， 136（45）， 15809—15812
7	Zhou X.， Wang C.， Chu Y. Y.， Wang Q.， Xu J.， Deng F.， Chem. Res. Chinese Universities， 2022， 38（1）， 155—160
8	Raqppoport Z.， Liebman J. F.， The Chemistry of Hydroxylamines， Oximes and Hydroxamic Acids， Part 1， Wiley， Chichester， 2009， 117—161
9	Mohr J.， Oestreich M.， Angew. Chem. Int. Ed.， 2014， 53（48）， 13278—13281
10	Mohr J.， Porwal D.， Chatterjee I.， Oestreich M.， Chem. Eur. J.， 2015， 21（49）， 17583—17586
11	Curless L. D.， Clark E. R.， Dunsford J. J.， Ingleson， M. J.， Chem. Commun.， 2014， 50（40）， 5270—5272
12	Rokob T. A.， Hamza A.， Stirling A.， Soós T.， Pápai I.， Angew. Chem. Int. Ed.， 2008， 47（13）， 2435—2438
13	Hamza A.， Stirling A.， Rokob T. A.， Pápai I.， Int. J. Quantum Chem.， 2009， 109（11）， 2416—2425
14	Grimme S.， Kruse H.， Goerigk L.， Erker G.， Angew. Chem. Int. Ed.， 2010， 49（8）， 1402—1405
15	Spies P.， Schwendemann S.， Lange S.， Kehr G.， Froehlich R.， Erker G.， Angew. Chem. Int. Ed.， 2008， 47（39）， 7543—7546
16	Liu L.， Cao L. L.， Shao Y.， Menard G.， Stephan D. W.， Chem， 2017， 3（2）， 259—267
17	Liu L.， Chem， 2017， 3（2）， 195—197
18	Hu X.， Tian C.， Maxim B.， Nie W.， Acta Chim. Sinica， 2015， 73（10）， 1025—1030
	胡茜，田冲， Maxim Borzov，聂万丽. 化学学报， 2015， 73（10）， 1025—1030
19	Tian C.， Jiang Y.， Maxim B.， Nie W. L.， Acta Chim. Sinica， 2015， 73（11）， 1203—1206
	田冲，姜亚， Maxim Borzov，聂万丽. 化学学报， 2015， 73（11）， 1203—1206
20	Zhang L. W.， Wen Z. G.， Maxim B.， Nie W. L.， Acta Chim. Sinica， 2017， 75（8）， 819—823
	张露文，温志国， Maxim Borzov，聂万丽. 化学学报， 2017， 75（8）， 819—823
21	Sun G. F.， He Y. Q.， Tian C.， Maxim B.， Hu Q. S.， Nie W. L.， Acta Chim. Sinica， 2019， 77（2）， 166—171
	孙国峰，何云清，田冲， Maxim Borzov，胡启山，聂万丽. 化学学报， 2019， 77（2）， 166—171
22	He Y. Q.， Teng J. W.， Tian C.， Maxim B.， Hu Q. S.， Nie W. L.， Acta Chim. Sinica， 2018， 76（10）， 774—778
	何云清，腾金伟，田冲， Maxim Borzov，胡启山，聂万丽. 化学学报， 2018， 76（10）， 774—778
23	He Y. Q.， Nie W. L.， Xue Y.， Hu Q. S.， RSC Adv.， 2021， 11（34）， 20961—20969

Entry	Silane	LB	t/h	λ/nm	Ratio	Conv.（%）^*
1	Ph₂SiH₂	t?Bu₃P	3	Visible	1∶2	63.3
2	Ph₂SiH₂	t?Bu₃P	6	Visible	1∶2	90.4
3	Ph₂SiH₂	t?Bu₃P	8	Visible	1∶2	90.8
4	Ph₂SiH₂	TMP	6	Visible	1∶2	85.4
5	Ph₂SiH₂	MeS₃P	6	Visible	1∶2	83.1
6	Ph₂SiH₂	—	6	Visible	1∶2	81.5
7	Ph₂SiH₂	MeS₃P	6	254	1∶2	N.D.
8	Ph₂SiH₂	MeS₃P	6	365	1∶2	77.6
9	PhSiH₃	MeS₃P	6	365	1∶1	91.0
10	Ph₃SiH	MeS₃P	6	365	1∶3	53.75
11	Et₃SiH	MeS₃P	6	365	1∶3	43.5
12	i?Pr₃SiH	MeS₃P	6	365	1∶3	N.D.

Entry	Silane	LB	t/h	λ/nm	Ratio	Conv.（%）^*
1	Ph₂SiH₂	t?Bu₃P	3	Visible	1∶2	63.3
2	Ph₂SiH₂	t?Bu₃P	6	Visible	1∶2	90.4
3	Ph₂SiH₂	t?Bu₃P	8	Visible	1∶2	90.8
4	Ph₂SiH₂	TMP	6	Visible	1∶2	85.4
5	Ph₂SiH₂	MeS₃P	6	Visible	1∶2	83.1
6	Ph₂SiH₂	—	6	Visible	1∶2	81.5
7	Ph₂SiH₂	MeS₃P	6	254	1∶2	N.D.
8	Ph₂SiH₂	MeS₃P	6	365	1∶2	77.6
9	PhSiH₃	MeS₃P	6	365	1∶1	91.0
10	Ph₃SiH	MeS₃P	6	365	1∶3	53.75
11	Et₃SiH	MeS₃P	6	365	1∶3	43.5
12	i?Pr₃SiH	MeS₃P	6	365	1∶3	N.D.

Entry	Silane	LA	LB	Enamine	λ/nm	Yield（%） ^a
1	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1b	365	56.00
2	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1c	365	58.00
3	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	365	90.00
4	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	Dark	69.70
5	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	Dark ^c	64.10
6	Ph₂SiH₂	B（C₆F₅）₃	—	1c	365	78.00 ^b
7	Ph₂SiH₂	—	MeS₃P	1c	365	N.D.
8	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1b	365	45.37
9	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1d	365	50.73
10	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1c	365	51.58
11	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1a	365	70.00
12	Ph₂SiD₂	B（C₆F₅）₃	TMP	1a	365	77.50
13	Ph₂SiD₂	B（C₆F₅）₃	t?Bu₃P	1a	365	80.25

Entry	Silane	LA	LB	Enamine	λ/nm	Yield（%） ^a
1	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1b	365	56.00
2	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1c	365	58.00
3	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	365	90.00
4	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	Dark	69.70
5	Ph₂SiH₂	B（C₆F₅）₃	MeS₃P	1d	Dark ^c	64.10
6	Ph₂SiH₂	B（C₆F₅）₃	—	1c	365	78.00 ^b
7	Ph₂SiH₂	—	MeS₃P	1c	365	N.D.
8	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1b	365	45.37
9	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1d	365	50.73
10	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1c	365	51.58
11	Ph₂SiD₂	B（C₆F₅）₃	MeS₃P	1a	365	70.00
12	Ph₂SiD₂	B（C₆F₅）₃	TMP	1a	365	77.50
13	Ph₂SiD₂	B（C₆F₅）₃	t?Bu₃P	1a	365	80.25

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