Diastereoselective Synthesis of Enantiopure C 2-Symmetric Dihaloferrocenes
31 December 2001 (online)
1,1′-bis[(S)-4-isopropyloxazolin-2-yl]ferrocene was dilithiated with sec-BuLi/TMEDA in Et2O to give a (p R:p R):(p R:p S) selectivity of 10:1. Following addition of C2Cl6 or C2Br2Cl4 the resulting dichloro and dibromo derivatives were subjected to oxazoline ring opening and further manipulation to provide enantiopure (p S,p S)-1,1′-dicarbomethoxy-2,2′-dihaloferrocenes, (p S,p S)-1,1′-di(hydroxymethyl)-2,2′-dihaloferrocenes and (p S,p S)-1,1′-dicarbaldehyde-2,2′-dihaloferrocenes.
ferrocenes - diastereoselectivity - halogens - metallations - oxazolines