W. Brill, A. De Mesmaeker, S. Wendeborn
Oct 1, 1998
Citations
0
Influential Citations
11
Citations
Journal
Synlett
Abstract
: Levoglucosan was decorated with a variety of substituents at various sites while being bound to a solid support. Levoglucosan has frequently been used as building block in the de novo synthesis of natural products 1 their analogs 2 and polymers 3 . Here we describe the use of the 6,8-dioxa-bicyclo[3.2.1]octane skeleton as a scaffold for the generation of a compound library. Herein the carbons 2, 3 and 4 on the levoglucosan scaffold were decorated with various alkoxy, thioxy or amino groups using epoxide opening and alkylation reactions. Moieties (R 1 , R 2 or R 3 ) bearing another amino or an aromatic iodo-function, were derivatized further using acylations or Pd-mediated coupling reactions (Scheme 1). We immobilized the scaffold onto “ Rink ”-amide resin ( 5 ) via various spacers (R 1 ). The levoglucosan-spacer adducts ( 4a-d ) were synthesized off bead from 1,6: 3,4- dianhydro-2-O-p -toluenesulfonyl- b -D-galactopyranose ( 1 ) 4 upon BF 3 - catalyzed epoxide opening with various methylester bearing alcohols ( 2a-d ). 5 The tosylated levoglucosan spacer conjugates ( 3a-d ) were then treated with LiOH to hydrolyze their methyl ester and generate the 2,3-epoxides ( 4a-d ). These lithium salts were then coupled to polystyrene or RAM-resin bearing “ Rink ”-NH 2 ( 5 ) using standard techniques.