4- Amino paracyclophane, reaction with

In 1993, our group reported that reaction of 4-amino[2.2]paracyclophane (8) with tetracyanoethylene (TCNE, 1) furnished the olefin 9 and oxaziridine 10 is the major product (Scheme 2). This interpretation was that initial CT complexation between 8 and 1 led to a formal conjugate adduct, which reacted further in one of two directions. The first route includes loss of HCN to give 9.The second route involves loss of malononitrile followed by addition of water and then cyclization to yield 10 (1993CJC1845). 

S R ratio = 5 1) [22]. Yanada and Yoneda constructed the deazaflavinophane 26, which exhibits complete facial selectivity in its oxidation and reduction reactions, e.g. the reduction with NaBD to afford 27 [23], Belokon and Rozen-berg used scalemic 4-formyl-5-hydroxy[2.2]para-cyclophane (FHPC) 28 in the synthesis of a-ami-no acids (ee 45-98 %) [24], An alternative approach to FHPC was more recently reported by Hopf [25]. Other interesting advances in the area of chiral cyclophanes include the homochir-al [2.2]paracyclophane-derived amino acids 29 and 30 [26], as well as (5)-PHANEPHOS (31) [27], which has been shown to be an effective ligand for highly enantioselective Ru-catalyzed asymmetric hydrogenations of -ketoesters and... 

Amino[2.2]paracyclophane and diamino[2.2]paracyclophane can be accessed by the nitration with trifluoromethanesulfonic acid/nitric acid and reduction of the nitro group with strategy incorporating triiron dodecacarb-onyl. F33(CO)i2 is a powerful reductant even under mild reaction conditions. Crown ethers are used as a phase transfer catalyst. The reaction scheme is shown in Figure 2.2. 

Enantioface differentiating reduction of arylglyoxylic acids can be performed with NaBH4 in aqueous buffer media using a modified CD, 6-deoxy-6-amino-p-cyclodextrin [78]. The reaction proceeds with high yields but the arylglycolic acids obtained had low ee. The use of water-soluble chiral paracyclophanes does not increase the enantioselectivity of the reaction. 

Cross-coupling reactions between amines and aryl halides or pseudohalides have been employed for the preparation of a number of chiral, nonracemic ligands for asymmetric catalysis. For example, early studies by Buchwald illustrated that chiral amino binaphthol derivatives could be generated by Pd-catalyzed Af-arylation of binaphthol-derived triflates (Eq. 74) [417]. A similar strategy was employed by Erase for the synthesis of planar-chiral [2.2]paracyclophane ligands (Eq. 75) [418]. The A -arylation of [2.2]paracyclophane-derived triflates has also been used for the construction of planar-chiral benzimidazoles [419]. The IV-arylation of a substituted pyrrolidine with 4-bromopyridine played a key role in the synthesis of a chiral nucleophilic catalyst related to DMAP [420]. 

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