Chemo- and diastereoselective control for a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones
摘要:
Chemo- and diastereoselective transformation of the N,O-acetals and their chain tautomers (4/5), readily derived from protected 3-hydroxyglutamide 1a, Was Studied. It Was Uncovered that while the reaction with a combination of boron trifluoride etherate/zinc borohydride led to cyclic products (5S,6S/R)-6-alkyl-5-benzyloxy-2-piperidinones 3/2, and 6 in modest chemo- and diastereoselectivities, the reaction of 4/5 with zinc borohydride led exclusively to the formation of the ring-opening products 6 in excellent anti-diastereoselectivities. On the basis of the latter reaction, a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones 3 was disclosed. (C) 2009 Elsevier Ltd. All rights reserved.
Chemo- and diastereoselective control for a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones
摘要:
Chemo- and diastereoselective transformation of the N,O-acetals and their chain tautomers (4/5), readily derived from protected 3-hydroxyglutamide 1a, Was Studied. It Was Uncovered that while the reaction with a combination of boron trifluoride etherate/zinc borohydride led to cyclic products (5S,6S/R)-6-alkyl-5-benzyloxy-2-piperidinones 3/2, and 6 in modest chemo- and diastereoselectivities, the reaction of 4/5 with zinc borohydride led exclusively to the formation of the ring-opening products 6 in excellent anti-diastereoselectivities. On the basis of the latter reaction, a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones 3 was disclosed. (C) 2009 Elsevier Ltd. All rights reserved.
A General and Simple Diastereoselective Reduction by L-Selectride: Efficient Synthesis of Protected (4S,5S)-Dihydroxy Amides
作者:Bo Yin、Dong-Nai Ye、Kai-Hui Yu、Liang-Xian Liu
DOI:10.3390/molecules15042771
日期:——
A general approach to (4S,5S)-4-benzyloxy-5-hydroxy-N-(4-methoxybenzyl) amides 10 based on a diastereoselective reduction of (5S,6RS)-6-alkyl-5-benzyloxy-6-hydroxy-2-piperidinones 6 and their tautomeric ring-opened keto amides 7 is described. The reduction with L-Selectride at -20 °C to room temperature afforded the products 10 in excellent yields and moderate to high syn-diastereoselectivities.