ENANTIOSELECTIVE SYNTHESIS OF NEW C-2-SYMMETRICAL FERROCENYLALKYLAMINES VIA SONOCHEMICAL AMINATION OF 1-FERROCENYLALKYL ACETATES

The synthesis of four new C-2-symmetric ferrocenylalkylamines, (R,R)-b is(1-ferrocenyl-ethyl)-amine (5), )-N,N'-bis-(1-ferrocenyl-ethyl)-etha ne-1,2-diamine (6), (R,R)-2,6-diferrocenyl-piperidine (7a), and (R,R)- 2,5-diferrocenyl-pyrrolidine (7b) is described. The syntheses are base d on the enantioselective, oxazaborolidine catalyzed borane reduction of acylferrocenes followed by S(n)1 amination, which can be accelerate d by ultrasound, as shown for the preparation of (R)-1-ferrocenyl-ethy lamine (15) in greatly improved yield. (C) 1997 Elsevier Science Ltd.