Stereomutation of a diastereomeric pair of 10‐P‐5 hydroxyphosphoranes

Kojima, Satoshi; Nakamoto, Masaaki; Matsukawa, Shiro; Akiba, Kin‐ya

doi:10.1002/hc.20712

“…Conversely, it is considerably longer than that of 1b [1.959(3)Å], [33] reflecting the increased bulk around the P-B bond. The P-O bond lengths [1.806(1)-1.807(1) Å] are considerably longer than those found in the hydroxyphosphorane [1.7059( 18)-1.7421( 18) Å], [50] but similar to those of 1b . [51] The long P-O bond lengths indicated localisation of substantially negative charges on the oxygen atoms and weakening of the polar P-O bonds.…”

Section: X-ray Crystallographic Analysismentioning

confidence: 67%

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

O'Brien¹,

Kano²,

Havare³

et al. 2020

Preprint

0

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The isolation and reactivities of two pentacoordinated<br>phosphorus–tetracoordinated boron bonded compounds were explored. A strong Lewis acidic boron reagent and electronwithdrawing ligand system were required to form the pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a unique rearrangement reaction, which involved a two-fold ring expansion, to give a fused bicyclic compound or it could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound, a phosphoranyl-triarylborate, was found to have different reactivity as it was highly stable towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure.<br>

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“…Conversely, it is considerably longer than that of 1b [1.959(3) Å], reflecting the increased bulk around the P–B bond. The P–O bond lengths [1.806(1)‐1.807(1) Å] are considerably longer than those found in the hydroxyphosphorane [1.7059(18)‐1.7421(18) Å], but similar to those of 1b [1.8102(17)‐1.8406(17) Å] and a phosphoranide‐palladium complex, [(2‐C 6 H 4 C(CF 3 ) 2 O) 2 P–Pd(PhCHO)(dppe)](SbF 6 ), [av. 1.780(3), 1.851(3) Å] .…”

Section: Resultsmentioning

confidence: 92%

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

O'Brien

¹

,

Kano

²

,

Havare

³

et al. 2020

View full text Add to dashboard Cite

The isolation and reactivities of two pentacoordinated phosphorus-tetracoordinated boron bonded compounds were explored. A highly Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the pentacoordinated phosphorus state of the P-B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a unique rearrangement, which involved a two-fold ring expansion, to give [ ‡] Current address:

show abstract

“…Conversely, it is considerably longer than that of 1b [1.959(3)Å], [33] reflecting the increased bulk around the P-B bond. The P-O bond lengths [1.806(1)-1.807(1) Å] are considerably longer than those found in the hydroxyphosphorane [1.7059(18)-1.7421(18) Å], [50] but similar to those of 1b The crystal structures of 3a and 3b were found to be in the Oapical pseudorotamer. This pseudorotamer is thought to be more stable and thus favoured due to high electronegativity of oxygen and the large steric bulk around the P-B bond, which can be observed in the space-filling model of the anion of 3b (Figure 2c).…”

Section: X-ray Crystallographic Analysismentioning

confidence: 80%

“…Conversely, it is considerably longer than that of 1b [1.959(3)Å], [33] reflecting the increased bulk around the P-B bond. The P-O bond lengths [1.806(1)-1.807(1) Å] are considerably longer than those found in the hydroxyphosphorane [1.7059(18)-1.7421(18) Å], [50] but similar to those of 1b 1.780(3), 1.851(3) Å]. [51] The long P-O bond lengths indicated localisation of substantially negative charges on the oxygen atoms and weakening of the polar P-O bonds.…”

Section: X-ray Crystallographic Analysismentioning

confidence: 80%

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

O'Brien¹,

Kano²,

Havare³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

The isolation and reactivities of two pentacoordinated<br>phosphorus–tetracoordinated boron bonded compounds were explored. A strong Lewis acidic boron reagent and electronwithdrawing ligand system were required to form the pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a unique rearrangement reaction, which involved a two-fold ring expansion, to give a fused bicyclic compound or it could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound, a phosphoranyl-triarylborate, was found to have different reactivity as it was highly stable towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure.<br>

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Stereomutation of a diastereomeric pair of 10‐P‐5 hydroxyphosphoranes

Cited by 12 publications

References 65 publications

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

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