Highly Regioselective Isomerization–Hydroformylation of Internal Olefins Catalyzed by Rhodium/Tetraphosphine Complexes

Cai, Chaoxian; Yu, Shichao; Liu, Guodu; Zhang, Xiaowei; Zhang, Xumu

doi:10.1002/adsc.201100139

Cited by 26 publications

(15 citation statements)

References 40 publications

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“…[12] Other examples are the isomerisation of allyl benzenes such as estragol or safrole, which are of great interest for the fragrance industry. [13,14] A wide range of isomerisation catalysts have been developed based on various metals such as Pd, [15][16][17] Ru, [18][19][20][21][22] Ti, [23][24][25] V, [26] Fe, [27][28][29] Rh, [30][31][32] Mo, [33] Ni, [34][35][36] etc., but also metal-free systems such as frustrated Lewis pairs. [37] One of the most active catalysts is the ruthenium-based "alkene zipper" developed by Grotjahn and co-workers.…”

Section: Introductionmentioning

confidence: 99%

Alkene Isomerisation Catalysed by a Ruthenium PNN Pincer Complex

Perdriau

Chang

Otten

et al. 2014

Chemistry A European J

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The [Ru(CO)H(PNN)] pincer complex based on a dearomatised PNN ligand (PNN: 2-di-tert-butylphosphinomethyl-6-diethylaminomethylpyridine) was examined for its ability to isomerise alkenes. The isomerisation reaction proceeded under mild conditions after activation of the complex with alcohols. Variable-temperature (VT) NMR experiments to investigate the role of the alcohol in the mechanism lend credence to the hypothesis that the first step involves the formation of a rearomatised alkoxide complex. In this complex, the hemilabile diethylamino side-arm can dissociate, allowing alkene binding cis to the hydride, enabling insertion of the alkene into the metal-hydride bond, whereas in the parent complex only trans binding is possible. During this study, a new uncommon Ru(0) coordination complex was also characterised. The scope of the alkene isomerisation reaction was examined.

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Section: Introductionmentioning

confidence: 99%

Alkene Isomerisation Catalysed by a Ruthenium PNN Pincer Complex

Perdriau

Chang

Otten

et al. 2014

Chemistry A European J

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“…In contrast, Boerner and co‐workers employed a phosphite ligand in the I‐HF of isomeric n ‐octenes, leading to better linear selectivity (up to 48 % n ‐nonanal) . Thus, a literature survey suggested that both (bis)phosphites and bisphosphine can catalyze isomerizing functionalization reactions of internal alkenes at elevated temperatures (120–140 °C) . Among the long‐chain plant oils, linear selective I‐HF of methyl oleate is found to be catalyzed by bisphosphite ligands of type L1 (Figure ) …”

Section: Resultsmentioning

confidence: 99%

Isomerizing Hydroformylation of Cashew Nut Shell Liquid

2017

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A small library of bisphosphorus ligands was evaluated in the rhodium‐catalyzed isomerizing hydroformylation (I‐HF) of cashew nut shell liquid (CNSL). The rhodium complex of 1,2‐bis((di‐tert‐butylphosphanyl)methyl)benzene (BDTBPMB; L4) outperformed the other bisphosphite and bisphosphine ligands and unveiled a moderate selectivity of 28 % and 50 % in the I‐HF of CNSL monoene and methoxy‐protected monoene, respectively. The resultant aldehyde 16‐(3‐methoxyphenyl)hexadecanal P1′ was isolated and its identity was fully established. Application of bis‐phosphine ligand L4 in the I‐HF of highly challenging CNSL cardanol (S3) and methoxy‐protected CNSL cardanol yielded a linear selectivity of 74 %, although with reduced conversion. To demonstrate the synthetic utility of our strategy, the obtained aldehyde (derived from S3) was subjected to hydrogenation and the resultant 3‐(16‐hydroxyhexadecyl) phenol (P8) was isolated in 89 % isolated yield. High‐pressure NMR investigation revealed selective formation of a bis‐equatorial BDTBPMB–rhodium complex, which might be responsible for the excellent linear selectivity.

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“…Several rhodium-based systems were developed in industry and academia for this demanding reaction. [17] Thus, the ruthenium-catalyzed hydroformylation of 2-octene was also investigated (Table 2). Unfortunately, no conversion was obtained by applying the standard reaction conditions developed for terminal alkenes (100 8C, 0.1 mol % Ru; Table 2, entry 1).…”

Section: Resultsmentioning

confidence: 99%