Isolation and characterization of some very stable 1-phospha-allenes: sterically protected iminomethylene- and ethenylidenephosphines

Yoshifuji, Masaaki; Toyota, Kozo; Shibayama, Katsuhiro; Inamoto, Naoki

doi:10.1016/s0040-4039(01)90047-4

Cited by 126 publications

(41 citation statements)

References 21 publications

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“…Starting from lithium t-butyldimethylsilyl-2,4,6-tri-t-butylphenylphosphide (1) we have been successful in the preparation of such unusual organophosphorus compounds as sterically protected E-and Z-2-t-butyldimethylsilyloxy-2-phenyl-l-(2,4,6-tri-t-butylpheny1)phosphaethylenes (2), ' 3,3-diphenyl-1-(2,4,6-tri-t-butylphenyl)-lphosphaallene (3),2 N-phenyl-P-(2,4,6-tn-t-butylphenyl)iminomethylenephosphine (4),2 and 1,3-bis(2,4,6-tri-t-butylphenyl)-1,3-diphospha~lene~ We …”

Section: Introductionmentioning

confidence: 99%

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Yoshifuji

Toyota

Inamoto

et al. 1985

Phosphorus and Sulfur and the Related Elements

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Section: Introductionmentioning

confidence: 99%

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Yoshifuji

Toyota

Inamoto

et al. 1985

Phosphorus and Sulfur and the Related Elements

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“…Correspondence phosphorus compounds of unusual structures, such as diphosphenes [4], phosphacumulenes [5][6][7][8][9][10][11], phospharadialenes [12], and phosphaquinones [13,14]. In the course of our continuing effort of developing new stabilizing groups and fine tuning of the stabilizing abilities of the substituents, we have examined various stabilizing groups such as 2,4-dit-butyl-6-methylphenyl (abbreviated to Dbt) [15,16], 2,4-di-t-butyl-6-(dimethylamino)phenyl (abbreviated to Mx) [17][18][19], 2,4-di-t-butyl-6-methoxyphenyl (abbreviated to Mox) [20][21][22], and 2,4-di-t-butyl-6-[1,1-dimethyl-2-(dimethylamino)ethyl]phenyl [23] groups.…”

Section: Introductionmentioning

confidence: 99%

Preparation and ³¹P NMR study of some low‐coordinated organophosphorus compounds bearing the 2,4‐di‐t‐butyl‐6‐isopropylphenyl group

Toyota

Matsushita

Shinohara

et al. 2001

Heteroatom Chemistry

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“…Such phosphaallenes are the shortest members of an intriguing class of P-terminated cumulenes, which have however been synthetically highly challenging with only sporadic reports in the literature. [7] Despite of the synthetic versatility of the pWH reaction, it has been a greatly underexplored method for the preparation of phosphaalkenes. At the same time, the reaction mechanism has hitherto been unknown.…”

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Mechanism of the Phospha‐Wittig–Horner Reaction

et al. 2013

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Phosphaalkenes are prominent ligands in homogenous catalysis due to their p-acceptor capacity [1] and are appealing building blocks in polymer science. [1b, 2] Methods for their preparation are however often limited by small substrate scopes, or residual OTMS substituents that stem from certain synthetic methods.[3] The phospha-Wittig-Horner (pWH) reaction, as first coined by Mathey and co-workers, [4] converts aldehydes and relatively unreactive ketones into C-monoand C,C-disubstituted phosphaalkenes, respectively (Scheme 1, top). Furthermore, the substituent at the phosphorus center can be chosen rather freely, although smaller groups demand additional stabilization by metal coordination.[5] In context of our previous work on the incorporation of low-valent phosphorus into unsaturated carbon scaffolds, [6] we were interested to see whether the scope of the pWH reaction could be extended to ketene substrates from which 1-phosphapropadienes would become accessible. Such phosphaallenes are the shortest members of an intriguing class of P-terminated cumulenes, which have however been synthetically highly challenging with only sporadic reports in the literature. [7] Despite of the synthetic versatility of the pWH reaction, it has been a greatly underexplored method for the preparation of phosphaalkenes. At the same time, the reaction mechanism has hitherto been unknown. Formally, the pWH reaction is the phosphorus analogue to the Horner-WadsworthEmmons reaction (HWE), which allows preparation of alkenes and allenes from carbonyl compounds and ketenes, respectively.[8] The mechanism of the HWE reaction has been studied in great detail over the last decades, with the crucial step being a simultaneous CÀP and CÀO bond cleavage in an intermediately formed oxaphosphetane to afford the desired alkene and the phosphate byproduct (Scheme 1, bottom).[9] In the spirit of the frequently drawn analogy between phosphorus and carbon, [10] it was assumed that the pWH reaction proceeds along a similar pathway. In the present report, we show for the first time that this assumption is wrong and that the pWH reaction proceeds in a more complex, stepwise fashion. The mechanism of the pWH reaction is elucidated with the aid of spectroscopically and crystallographically characterized reaction intermediates.The present study is based on two pWH reagents that are stabilized by {W(CO) 5 } fragments but differ in the P III substituent (1, 2), [5a] and two substrate ketenes, one with phenyl substituents (3), the other with a fused fluorenyl core (4). As for all HWE and pWH reactions, the reactions are initiated by the addition of base. Thus, stoichiometric amounts of organic base (1,8-diazabicyclo[5.4.0]undec-7-ene, DBU) were added to 1 or 2 followed by the addition of either ketene 3 or 4. The products that were obtained after 30 min and aqueous workup were however not the expected phosphaallenes, but previously unknown phosphinophosphates 5 a-d (Scheme 2).Complexes 5 a-d are obtained as pale yellow solids in good to excellent yields. The...

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Isolation and characterization of some very stable 1-phospha-allenes: sterically protected iminomethylene- and ethenylidenephosphines

Cited by 126 publications

References 21 publications

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Preparation and ³¹P NMR study of some low‐coordinated organophosphorus compounds bearing the 2,4‐di‐t‐butyl‐6‐isopropylphenyl group

Mechanism of the Phospha‐Wittig–Horner Reaction

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Isolation and characterization of some very stable 1-phospha-allenes: sterically protected iminomethylene- and ethenylidenephosphines

Cited by 126 publications

References 21 publications

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Structures of Phosphaethylenes and a 1-Phosphaallene Containing Phosphorus in Lower Coordination State

Preparation and 31P NMR study of some low‐coordinated organophosphorus compounds bearing the 2,4‐di‐t‐butyl‐6‐isopropylphenyl group

Mechanism of the Phospha‐Wittig–Horner Reaction

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Preparation and ³¹P NMR study of some low‐coordinated organophosphorus compounds bearing the 2,4‐di‐t‐butyl‐6‐isopropylphenyl group