Synthesis of Enantiopure P-Stereogenic Diphosphacrowns using P-Stereogenic Secondary Phosphines

Morisaki, Yasuhiro; Kato, Ryosuke; Chujo, Yoshiki

doi:10.1021/jo302748x

Cited by 13 publications

(7 citation statements)

References 36 publications

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“…We tried to construct a 24‐tetraphosphacrown‐8 structure containing rigid benzene rings. In our previous report, benzo‐12‐diphosphacrown‐4 ( R,R )‐ 6 a⋅ BH 3 was obtained by using 1,2‐bis(2‐hydroxyethoxy)benzene ditosylate ( 4 a ) as an electrophile, whereas the target 24‐tetraphosphacrown‐8 ( R,R,R,R )‐ 5 a⋅ BH 3 could not be isolated (Scheme ) . Therefore, we synthesized ( R,R,R,R )‐ 5 a⋅ BH 3 via the stepwise reaction, as shown in Scheme .…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we have focused on P‐stereogenic phosphines and synthesized optically active polymers, oligomers, and cyclic compounds containing these units in the main skeleton, by using P‐stereogenic bisphosphine borane complexes developed by the groups of Evans and Imamoto . In particular, a practical synthetic route to P‐stereogenic diphosphacrowns has been developed . The key point of the synthetic method is to employ a secondary P‐stereogenic bisphosphine borane complex as an optically active element‐block that can be readily lithiated by butyllithium for further reaction with a variety of electrophiles.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of P‐Stereogenic Tetraphosphacrowns

2015

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Synthetic routest oe nantiopure P-stereogenic tetraphosphacrowns, containing four chiral phosphorus atoms, using aP -stereogenic secondaryb isphosphine are reported. 18-Tetraphosphacrown-6 and 24-tetraphosphacrown-8 derivatives were prepared by as ingle-step and multistep method, respectively,a nd their characterizationsa re described in detail. Removal of boranes from the 24-tetraphosphacrown-8 derivative and subsequent complexation with platinum(II) are also described. Results and DiscussionFirst we tried to synthesize an 18-membered P-stereogenic tetraphosphacrown by ao ne-pot reactionf rom as econdary bisphosphine and diethylene glycol bis(p-toluenesulfonate);t he reactiono ft he (S,S)-isomer is shown in Scheme 1. The synthetic route to the secondary bisphosphine (S,S)-1·BH 3 has already been established by CrØpy and Imamoto. [19] After dilithiation of (S,S)-1·BH 3 with nBuLi in THF at À78 8C, the addition of diethylene glycol bis(p-toluenesulfonate) as an electrophile provided am ixture of the target 18-tetraphosphacrown-6 (R,R,R,R)-2·BH 3[a] R.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of P‐Stereogenic Tetraphosphacrowns

2015

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“…[111][112][113] There are several optically active polymers whose structures are highly controlled by repeating asymmetric reactions; however, optically active polymers including chiral heteroatoms in the main chain are limited. In our group, we have successfully reported oligomers, [114][115][116][117] polymers, 118-123 dendrimers 124 and macrocycles, [125][126][127][128][129][130][131][132][133] including chiral phosphorus atoms in the main chain, and we have revealed their properties and potential applications. Recently, we have focused on diphosphacrowns as a kind of P-stereogenic cyclic phosphine and synthesized various types of optically active diphosphacrowns with P-stereogenic bisphosphineborane complexes.…”

Section: P-stereogenic Cyclic Phosphines For Chiral Element-blocksmentioning

confidence: 99%

“…We developed a new synthetic route that afforded enantiopure diphosphacrowns in substantially better isolated yields than the previous method. 129 Scheme 4 describes the synthetic route to the target (R,R)-benzodiphosphacrowns (R,R)-11-BH 3 from the P-stereogenic bisphosphine-borane complex (R)-12-BH 3 . The key point for improving the yield was to use (S,S)-10-BH 3 as a precursor.…”

Section: P-stereogenic Cyclic Phosphines For Chiral Element-blocksmentioning

confidence: 99%

Recent progress in the development of advanced element-block materials

Gon

Tanaka

Chujo

2017

Polym J

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140

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An element-block is defined as a minimum functional unit composed of heteroatoms. The concept of 'element-block material' for designing advanced materials was proposed in 2015. In this review, the recent progress in material designs based on this concept is described. From our research, several element-blocks as representative examples are selected, and their roles in each material are explained. Initially, research on the development of 'designable hybrids' by employing polyhedral oligomeric silsesquioxane (POSS) is illustrated. Multiple functions of hybrids composed of modified POSS and the significant roles of POSS in bio-related polymeric materials for solving critical problems in conventional 19 F MR probes and for realizing new sensing technologies are demonstrated. Next, solid-state luminescent materials containing o-carborane and group 13 element-blocks are discussed. The materials' highly efficient emission in the solid state and their origins are explained. Furthermore, stimuliresponsive luminescent chromism is summarized. The sensing mechanisms and the application of these materials as sensors are presented in this study. In the last part, we mention optically active element-blocks containing chiral P-stereogenic phosphorus. In this review, the characteristics originating from each element-block are explained.

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“…Phosphine is conformationally stable because of the high inversion energy barrier of the phosphorus atom, which allows the phosphorus atom to become a chiral center . We have developed practical synthetic routes to enantiopure P‐stereogenic benzodiphosphacrowns by using an optically active bisphosphine as a chiral element block . Phosphorus exhibits a high affinity towards transition metals, and phosphines can be used as ligands for transition‐metal‐catalyzed asymmetric reactions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Alkali-Metal-Ion Complexation of P-Stereogenic Diphosphacrowns

2016

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Phosphine is conformationally stable because of the high inversion energy barrier of the phosphorus atom, which allows the phosphorus atom to become a chiral center. Thus, enantiopure P‐stereogenic 12‐, 15‐, 18‐, and 21‐membered aliphatic phosphines “diphosphacrowns” were synthesized from secondary P‐stereogenic bisphosphine as a chiral building block. Their complexation behaviors with alkali metal ions are investigated in comparison with benzo‐18‐diphosphacrown‐6 and benzo‐18‐crown‐6. 15‐, 18‐, and 21‐Membered diphosphacrowns captured alkali metal ions to form 1:1 metal complexes. Unique guest selectivity was observed, as diphosphacrowns encapsulated smaller alkali metal ions than common crown ethers; for example, 18‐membered diphosphacrowns interacted more strongly with Na+ than K+. The difference in guest selectivity between diphosphacrowns and common crown ethers is speculated to result from the cavity size, owing to the large phosphorus atom as well as steric hindrance around the phosphine moiety.

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Synthesis of Enantiopure P-Stereogenic Diphosphacrowns using P-Stereogenic Secondary Phosphines

Cited by 13 publications

References 36 publications

Synthesis of P‐Stereogenic Tetraphosphacrowns

Synthesis of P‐Stereogenic Tetraphosphacrowns

Recent progress in the development of advanced element-block materials

Synthesis and Alkali-Metal-Ion Complexation of P-Stereogenic Diphosphacrowns

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