301298-60-2

Upstream product

• 301298-50-0 2,5-di-O-(p-methoxybenzyl)-1,6-di-O-(p-toluenesulfonyl)-D-mannitol 
• 301298-47-5 1,3:4,6-di-O-benzylidene-2,5-bis-O-(p-methoxybenzyl)-D-mannitol 
• 301298-48-6 2,5-di-O-(p-methoxybenzyl)-D-mannitol 
• 301298-58-8 (2S)-1-O-(1'-ethoxyethyl)-2-O-(p-methoxybenzyl)-3-O-(p-toluenesulfonyl)glycerol 
• 301298-52-2 (2S)-2-O-(p-methoxybenzyl)-3-O-(p-toluenesulfonyl)glycerol 
• 824-94-2 p-methoxybenzyl chloride 

Relevant academic research and scientific papers

Strategies for the formation of 1-dethia-1-oxa-cephams

The paper describes three possible routes for the formation of 1-dethia-1-oxa-cephams. The first two routes: (a) [2+2]cycloaddition to chiral vinyl ethers and (b) condensation of 4-acetoxyazetidin-2-one to chiral alcohols, are followed by the ring closure step involving N-alkylation. The third route (c) consists of N-alkylation prior to the cyclization step. In order to compare routes (a), (b) and (c), diastereomeric 1-dethia-3-(4-methoxybenzyloxy)-1-oxacephams were synthesized using three possible strategies. While the comparison of stereoselectivities of the [2+2]cycloaddition method (a) and the condensation (b) shows unequivocally the advantage of the former, the route (c) leads to the reverse direction of asymmetric induction relative to the first two steps and offers the highest asymmetric induction. (C) 2000 Elsevier Science Ltd.