Synthesis and configurational analysis of phosphonate cavitands

Synthesis and Binding Properties of iiii (4i) Stereoisomers of Phosphonato Cavitands − Cooperative Effects in Cation Complexation in Organic Solvents

“…The findings were the same as the literature ones: No 4i or 3io isomers could be characterized, only a mixture consisting especially of the ioio, the 2i2o and the 3oi isomers. [34] [27] From the differences in the experimental procedures, it seems likely that the solvent/amine pair plays a crucial role in the formation of the 4i stereoisomer, and this is supported by the following observations. Firstly, the procedure is highly solvent-dependent; the 4i stereoisomer is the major product obtained in toluene, but other isomers (ioio, 2i2o, 3oi) are predominant and the 4i stereoisomer is not observed when the reaction is run in acetone.…”

“…However, it is noteworthy that no other isomers were recovered, indicating a reaction pathway different to that developed by the Dalcanale group (compare Entries 4 and 6 in Table 1). [27] According to this latter literature procedure, we tried to perform the ring-closure reaction with 4a in acetone instead of toluene (see Entry 7, Table 1). The findings were the same as the literature ones: No 4i or 3io isomers could be characterized, only a mixture consisting especially of the ioio, the 2i2o and the 3oi isomers.…”

“…[26] In the case of the phenylphosphonate derivatives, the presence of the four P(O)Ϫphenyl groups should make the likelihood of more than one phenyl substituent being oriented inwards even more remote, but a synthetic pathway recently described afforded mainly the 3oi, 2i2o and ioio stereoisomers. [27] In earlier work, we have demonstrated that the tetraphosphonato cavitand 2 can be obtained exclusively as its 4i stereoisomer in fairly good yields. [29] We wish to report here experimental evidence of the directed syntheses of the 4i stereoisomers of the tetraphosphonato cavitands 2 and 3, with the four PϭO groups oriented inwards.…”

ESI-FTICR mass spectrometric study of alcohol complexation properties of mono- and diphosphonate-bridged cavitands

“…Mean In earlier studies on similar cavitands, the relative configuration [43] and number of P ϭ O groups have been found strongly to affect the efficiency of complex formation. In the case of alkyl ammonium ion guests, the presence of two or more inward-directed P ϭ O groups allowed the formation of several hydrogen bonds with the guests and increased the abundance of complexes [32].…”

Regioselective Grafting of Two –CH2P(X)Ph2 Units (X = O, Lone Pair) onto a Resorcin[4]arene‐Derived Cavitand

“…[11][12][13][14][15][16] Mainly for synthetic reasons, only one phosphane ligand derived from a resorcinarene -the tetraphosphane 1 [4] -has been described in the literature, but a number of other phosphorus-functionalised resorcinarenes have already been reported. [17][18][19][20][21][22] Diphosphanes based on the same skeleton, which are potential precursors of bimetallic and chelate complexes, and therefore of complexes of catalytic relevance, have not yet been reported.…”