The supramolecular structures and reactivities of some complexes of chiral crown ethers with borane ammonia

Abstract

Whereas 1 : 1 crystalline complexes have been isolated between borane ammonia and methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-galactopyranosido [2,3-b]-1,4,7,10,13,16-hexaoxacyclo-octadecane (1), methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido [2,3-b] (methyl 4′,6′-O-benzylidene-2′,3′-dideoxy-α-d-mannopyranosido [2′,3′-k]-1,4,7,10,13,16-hexaoxacyclo-octadecane (3), and (1 R,2 R,7 R,24 R)-3,5,8,11,14,17,20,23,26,28-decaoxatricyclo-[21.4.0.02,7]octacosane (4), the hosts, methyl, 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido[2,3-b] 1,4,7,10,13,16-hexaoxacyclo-octadecane (2) and 1,4 : 1′,4′ : 3,6 : 3′,6′-tetra-anhydro-2,2′ : 5,5′-bis-O-oxydiethylenedi-d-mannitol (5) have yielded 2 : 1 (guest:host) crystalline complexes with borane ammonia as guest. X-ray analyses of the supramolecular structures of BH3NH3 ·1, (BH3NH3)2 ·2, BH3NH3 ·3, BH3NH3 ·4, and (BH3NH3)2 ·5 have been carried out and BH3NH3 ·1, BH3NH3 ·2, and (BH3NH3)2 ·5 have been shown to reduce acetophenone with enantiomeric excesses of 5, 13, and 10% respectively. © 1985 D. Reidel Publishing Company.