Synthesis of novel paracyclophanes with linear P,N-containing spacers

Abstract

Condensation of bis(hydroxymethyl)mesityl and bis(hydroxymethyl)phenylphosphines with N,N´ disubstituted bis(4 aminophenyl)methanes and bis(4 amino 3 carboxy phenyl)methane occurred as covalent self assembly spontaneously giving a mixture of trans and cis diastereomers of 1,5,19,23 tetra R´ 3,21 di R 1,5,19,23 tetraaza 3,21 diphospha[5.1.5.1]paracyclophanes as the major products. The trans isomer (R is mesityl; R´ is methyl) was isolated in the individual state and structurally characterized by X ray diffraction analysis. Sulfurization of macrocyclic diphosphines (R = Ph; R´ is 3 pyridylmethyl or 4 pyri dylmethyl) gave the corresponding diphosphine disulfides, the trans stereoisomer being iso lated in the individual state.Macrocycles containing soft electron donating sites (in particular, tricoordinate phosphorus atoms) are of con stant interest primarily as a basis for development of cata lytic systems with reactive sites inside or adjacent to the macrocyclic cavity. 1,2 In such macrocycles, secondary in teractions of the cavity with substrates and reagents be come possible, thus making catalytic processes more effi cient and selective. Specific catalytic properties have been discovered with both macrocycles containing phosphine sites at the periphery of the cavity (such as phosphino cyclodextrins, 3,4 phosphinocalixarenes, 5 and cyclophanes with exocyclic phosphino groups (e.g., PhanePhos 6 ) and compounds with P atoms in the macrocycle itself. 1,2 In addition, phosphorus containing macrocycles are of in terest for design of supramolecular systems: receptors and sensors with specific properties. 7,8 From either point of view, cyclophanes with tricoordinate phosphorus atoms in the macrocycles composed of aromatic building blocks (e.g., m and p arylene fragments capable of forming deep hydrophobic cavities) are attractive. However, despite a great number of known P containing macrocycles, de scribed 9-11 cyclophanes of this type are relatively few, mostly including macrocyclic diphosphites, diphospho nites, and bis(phosphoramidites). 11-16 Recently, we have developed an efficient approach to the synthesis of cage type cyclophanes containing four phosphine sites, namely, 1,5(1,5) di(1,5 diaza 3,7 diphosphacyclo octana) 2,4,6,8(1,4) tetrabenzenacyclooctaphanes. The approach involves condensation of bis(hydroxymethyl)or ganylphosphines with primary diamines containing spac ers formed by two p phenylene fragments linked by vari ous monoatomic bridges. 17,18 At high concentrations of the reagents and in the absence of templates, those reac tions mainly yielded macrocycles via covalent self as sembly. 18 The goal of the present work was to further develop this approach and use it for the synthesis of more flexible cyclophanes with two tricoordinate P atoms in the macrocycle. To solve this problem, here we studied reactions of bis(hydroxymethyl)phenyl and bis(hydroxymethyl)mesitylphosphines with a number of secondary diamines containing di(p phenylene)me thane spacers: bis(4 methylaminophenyl)methane 1 (see Ref. 19), bi...

An effective strategy of P,N-containing macrocycle design

“…The relative content of the corresponding products was about 75-80%, but only macrocycles 30 and 31 were isolated in the yields of 21 and 67%, respectively. The similar product 32 was obtained as a very viscous oil of 85% purity which contained also the unidentified oligomeric aminomethylphosphine byproducts [25].…”

“…The macrocycles 30-32 were formed as the mixtures of cis-and trans-stereoisomers. The trans-isomers prevailed in the reaction mixtures only slightly, but the fractional crystallization of 30 from DMF led to the individual transstereoisomer [25].…”

“…It should be mentioned that the equivalence of all phenylene rings and methyl groups on nitrogen atoms in 1 = NMR spectra of 30 gives the evidence of the fast conformational exchange in solutions of this macrocycle [25].…”

“…The neighbouring phenylene rings are strongly twisted and the angle between their planes is 69.78. The opposite rings are coplanar, and different pairs of rings are inclined to the reference plane of the macrocycle at the angles of 73.1 and 138.68 respectively, so the macrocyclic cavity is practically collapsed and elongated: the P-P-distance is 11.80 A ˚, whereas the distance between the opposite aromatic rings is only 5.85 A ˚ [25].…”

Phospha-Mannich reactions of RPH2, R2PH, and R3P

“…3 CH 2 H 67 [14,15] -40.3 (CHCl 3 ) 4 CH 2 H 82* [14,15] -37.7 (DMF) 5 CH 2 Me Me 21 [14,15] -41.3 (DMF-d 7 )…”