New chiral bis(triarylphosphine) ligands, trans-bis(3-diphenylphosphinophenyl)cyclopentane and trans-bis(2-diphenylphosphinophenyl)cyclopentane, have been prepared in opticallypure forms based on asymmetrichydrogenation of 4,5-diaryl-2-oxocyclopentanecarboxylates catalyzed by the BINAP—Ru(II) complex.
Reduction of 1,2-diaryl-substituted ethenes with Na metal in dry THF allowed easy access to a variety of 1,2-diaryl-1,2-disodiumethanes. These diorganometallic intermediates were elaborated into the corresponding 1,2-diarylethanes (aqueous work up), or cycloalkylated with 1,3-dichloropropanes. The last reaction led to a highly diastereoselective synthesis of trans-1,2-diaryl-substituted cyclopentanes. (c) 2005 Elsevier Ltd. All rights reserved.