Synthesis and Reactivity of ortho-Carbaborane-Containing Chiral Aminohalophosphines

Abstract

The synthesis of chiral ortho-carbaboranyl bis(aminohalophosphines) is presented, and spectroscopic and crystallographic data of these compounds are discussed. Furthermore, their reactivity toward alcoholysis was investigated. Quantum chemical calculations showed that the inhibition of methanolysis is of kinetic and not of thermodynamic origin. The disubstitution of the carbaboranes leads to P...P interactions as strong as a hydrogen bond that extremely lower the rate of the methanolysis.

Exploiting the Ring Strain of Diphosphetanes: A Synthetic and Computational Approach towards 1,2,5‐Selenadiphospholanes

“…Both compounds show an envelope conformation of the C 2 P 2 Se ring and a trigonal‐pyramidal geometry around the phosphorus atoms (Figure ). The C cluster −C cluster bond length as well as the bond angles around the phosphorus atoms in both compounds have similar values to those found in diphospholane diselenide III and are comparable to previously published carborane‐substituted bisphosphanes ,,. The P−Se and P=Se bond lengths as well as the P−Se−P angles observed in both compounds are within the range of published values for diphospholane diselenides Ia , Ib and III , as well as the open‐chain diphosphaselenanes VI .…”

Highly Water‐Soluble Carbaborane‐Bridged Bis(glycophosphonates)

“…[23] Both phosphorus atoms have a pyramidal environment, and the four nitrogen atoms are surrounded in a trigonal-planar fashion by the methyl groups and the phosphorus atom.…”

“…The P(1)-C(1) and the P(2)-C(2) bond lengths are in the same range as in the meta-carbaborane derivative 7 and similar ortho-carbaborane derivatives. [23] Compound 15 was treated with an excess of protected galactose 2 under microwave conditions. Interestingly, the reaction proceeds faster than with meta-carbaborane analogue 7.…”

Unusual Absence of Head-to-Tail Chains in the Crystal Structure of Glycyl-l-glutamyl-l-phosphoseryl-l-leucine

“…After each coupling step the Fmoc-protecting group was removed and the deprotection solution was collected and used to estimate the loading by UV/Vis at 301 nm (e = 7,800 M -1 L -1 ) [11]. The phosphorylation reagent dibenzyl N,N-diisopropylphosphoramidite and the activator 4,5-dicyanoimidazole were prepared according to literature procedures [12][13][14]. For the phosphorylation, the resin was dried in vacuo overnight.…”