5 -formyl-4 -hydroxy paracyclophane

Vogtle et al. have prepared chiral poly(imine) dendrimers of various generations by condensation of non-racemic 5-formyl-4-hydroxy[2.2]paracyclophane moieties with poly(amine) dendrimers [71]. They have found that the optical activity of these dendrimers was nearly constant with increasing generation number. 

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... 

The synthesis of coumarins by the base-promoted condensation of ethyl nitroacetate with salicylaldehydes has been applied to 4-formyl-5-hydroxy[2.2]paracyclophane which... 

Formyl-5-hydroxy[2.2]paracyclophane (153) was used as a chiral auxiliary in the synthesis of a-amino acids [98]. The reported enantiomeric excess was in the range of 90-98%. Racemic 153 was first prepared by Hopf and Barrett [99]. To separate the enantiomers, their Schiff bases with the dipeptide (S)valyl-(S)valine was prepared. The diastereomeric copper(II) complexes of this compound show different solubility in 2-propanol. Alternatively they can be separ-... 

Scheme 49. 4-Formyl-5-hydroxy[2.2]paracyclophane and diastereoselective nucleophile additions [100]...

---