Chiral linker. Part 4: Diastereoselective addition of RZnX to α-keto esters using m-hydrobenzoin derived chiral auxiliaries in solution and on solid support and their application in the stereoselective synthesis of frontalin
摘要:
Two recently reported, m-hydrobenzoin derived open chain chiral auxiliaries, which were developed for application in either solution or immobilized on a solid support, were tested in the diastereoselective addition of RZnX to their corresponding phenylglyoxylates and pyruvates, respectively, resulting in diastereoisomeric excesses of up to > 98% de. The optimized procedure was applied in the stereoselective synthesis of frontalin, the aggregation pheromone of pine bark beetles of the Dendroctonus family, by the use of both the solution phase and the polymer supported chiral auxiliary. (c) 2006 Elsevier Ltd. All rights reserved.
Chiral linker. Part 2: Synthesis and evaluation of a novel, reusable solid-supported open chain chiral auxiliary derived from m-hydrobenzoin for the diastereoselective reduction of α-keto esters
摘要:
Three novel m-hydrobenzoin derived chiral hydrobenzoin mono-alkyl ethers were synthesized and evaluated as open chain chiral auxiliaries in the L-selectride(R)/ZnCl2 mediated stereoselective reduction of their corresponding phenyl glyoxylates, resulting in des of up to 91%. The optimized auxiliary structure was immobilized on commercially available Wang-resin by using the ether substituent as a sublinking unit and applied as a reusable solid-supported chiral auxiliary in the same type of reaction with only little loss of stereofacial selectivity. (c) 2005 Elsevier Ltd. All rights reserved.
Chiral linker. Part 4: Diastereoselective addition of RZnX to α-keto esters using m-hydrobenzoin derived chiral auxiliaries in solution and on solid support and their application in the stereoselective synthesis of frontalin
Two recently reported, m-hydrobenzoin derived open chain chiral auxiliaries, which were developed for application in either solution or immobilized on a solid support, were tested in the diastereoselective addition of RZnX to their corresponding phenylglyoxylates and pyruvates, respectively, resulting in diastereoisomeric excesses of up to > 98% de. The optimized procedure was applied in the stereoselective synthesis of frontalin, the aggregation pheromone of pine bark beetles of the Dendroctonus family, by the use of both the solution phase and the polymer supported chiral auxiliary. (c) 2006 Elsevier Ltd. All rights reserved.
Chiral linker. Part 2: Synthesis and evaluation of a novel, reusable solid-supported open chain chiral auxiliary derived from m-hydrobenzoin for the diastereoselective reduction of α-keto esters
Three novel m-hydrobenzoin derived chiral hydrobenzoin mono-alkyl ethers were synthesized and evaluated as open chain chiral auxiliaries in the L-selectride(R)/ZnCl2 mediated stereoselective reduction of their corresponding phenyl glyoxylates, resulting in des of up to 91%. The optimized auxiliary structure was immobilized on commercially available Wang-resin by using the ether substituent as a sublinking unit and applied as a reusable solid-supported chiral auxiliary in the same type of reaction with only little loss of stereofacial selectivity. (c) 2005 Elsevier Ltd. All rights reserved.