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The aryl[2.2]paracyclophane backbone, which is a "hybrid" of a configurationally rigid [2.2]paracyclophanyl unit and a biphenyl unit, is proposed as a new source for the chiral ligands. Classification of such ligands in accordance with mutual arrangement of the functional substituents and their nature is also introduced. Key strategic approaches to the synthesis of regioisomeric biphenols and hydroxyaldehydes, including Suzuki cross-coupling reaction, lithiation/electrophilic quench, and chiral resolution, are elaborated. Examples of their further modification and application of several O,O- and N,O-ligands as chiral inductors in asymmetric catalysis are described.

Allylboronic esters with various structures were synthesized for the first time based on [2.2]paracyclophane derivatives containing one or two hydroxy groups. It was demonstrated that these esters can be used as chiral inductors in the asymmetric allylboration of benzalde hyde. The highest enantiomeric excess of 1 phenylbut 3 en 1 ol (60%) was achieved in the reactions with acyclic bis O,O´ (paracyclophanyl) allylboronates based on (S) 4 hydroxy and (S) 12 bromo 4 hydroxy[2.2]paracyclophanes. (S) 4 Hydroxy[2.2]paracyclophane was studied by X ray diffraction.The allylboration of aldehydes is one of the most widely used approaches to the stereoselective C-C bond forma tion. 1-4 Generally, enantiomerically pure compounds (diols, diamines, sulfamides, and amino alcohols) pos sessing central 4 or (more rarely) axial chirality 5 are used for the design of reagents for the asymmetric allylboration.Earlier, 6,7 we have demonstrated for the first time that planar chiral [2.2]paracyclophane derivatives can be used in this reaction. For example, diastereomerically pure diallylborinate 2 was synthesized starting from 4 acetyl[2.2]paracyclophane (1) 8,9 (Scheme 1).Compound 2 was used in the allylboration of 4 for myl[2.2]paracyclophane (4) (de of rel (R p ,R) 4 (1 hydr oxybut 3 enyl)[2.2]paracyclophane (5) 50%) and benz aldehyde (6) (ee of 1 phenylbut 3 en 1 ol (7) was 18%). Homoallylic alcohol 3 produced in the reaction is a re cyclable auxiliary because it again gives ester 2 in the reaction with triallylborane (see Scheme 1).In alcohol 3, the hydroxy group is two bonds from the paracyclophane moiety. In the present study, we investi gated the influence of the distance between the functional group and the paracyclophane moiety on the stereochemi cal result of asymmetric allylboration of benzaldehyde. For this purpose, we examined for the first time the possi bility of designing reagents for the asymmetric allyl boration based on chiral phenols, viz., (S) 4 hydr oxy[2.2]paracyclophane (8) and (S) 12 bromo 4 hydr oxy[2.2]paracyclophane (9), in which the hydroxy group is directly fixed in the aromatic ring of [2.2]paracyclo phane.An important feature, which distinguishes phenols 8 and 9 from alcohol 3 containing two stereogenic centers, is that they contain only one (planar) chirality center, which eliminates the question about the possible coop erative effect of the planar and central chirality in the asymmetric process. Results and DiscussionSynthesis of starting phenols 8 and 9. Racemic phenol 8 was synthesized according to a known procedure. 10 To synthesize its enantiomers, we have developed 11-14 a pro cedure for the resolution of rac 8 into enantiomers through esters with (1S) (-) camphanic acid 10 (Scheme 2). 15, 16 Diastereomeric esters 10 were separated by fractional crystallization 15 followed by the preparative separation of the mother liquor by silica gel column chromatography. 16 In the present study, we improved the procedure for the isolation of enantiomers of phenol 8 from diastereo merically pure esters by us...

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