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Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds
Author(s) -
O'Brien Nathan J.,
Kano Naokazu,
Havare Nizam,
Uematsu Ryohei,
Ramozzi Romain,
Morokuma Keiji
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000229
Subject(s) - chemistry , hydroboration , borane , reactivity (psychology) , boranes , reagent , regioselectivity , boron , medicinal chemistry , lewis acids and bases , ligand (biochemistry) , bicyclic molecule , stereochemistry , organic chemistry , catalysis , medicine , biochemistry , alternative medicine , receptor , pathology
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 a fused bicyclic compound or it could act as a mono‐hydroboration reagent. The hydroboration reactivity of the intermediate was found to be higher towards alkynes vs. 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.