Enantiospecific synthesis of (S)-(−)-8-oxoxylopinine
作者:Zofia Meissner、Maria Chrzanowska
DOI:10.1016/j.tetasy.2015.01.002
日期:2015.2
The enantiospecific synthesis of (S)-(-)-8-oxoxylopinine 1 was performed using a lateral metallation strategy, in which (S)-alaninol or (S)-phenylalaninol was applied as chiral auxiliary and building block. (4S)-3-(4,5-Dimethoxy-2-methylbenzoy1)-2,2,4-trimethyl-1,3-oxazolidine 12 was synthesized starting from veratraldehyde 13. The addition reaction of benzylic anion generated in situ from chiral amide 12 into 6,7,-dimethoxy-3,4-dihydroisoquinoline 7a proceeded with simultaneous cyclization leading to the protoberberine alkaloid with high enantioselectivity. (C) 2015 Elsevier Ltd. All rights reserved.
Synthesis of Both Enantiomers of Protoberberines via Laterally Lithiated (S)-4-Isopropyl-2-(o-tolyl)oxazolines