Synthesis of two (S)-indoline-based chiral auxiliaries and their use in diastereoselective alkylation reactions
作者： Fredrik Andersson , Erik Hedenström
DOI: 10.1016/J.TETASY.2006.07.002
关键词: Butyl iodide 、 Stereocenter 、 Selectivity 、 Alkylation 、 Chemistry 、 Benzyl bromide 、 Organic chemistry 、 Indoline 、 Diastereomer
摘要: Abstract Two chiral auxiliaries, 2-[( S )-indolin-2-yl]propan-2-ol 1a and ( )-2-(2-methoxypropan-2-yl)indoline 1b , were synthesised from enantiomerically pure )-indoline-2-carboxylic acid 3 . High diastereoselectivities in alkylations of enolates the propanoylamides derived two auxiliaries are presented. Surprisingly, both induced same selectivity at newly created stereogenic centre. The benzyl bromide n -butyl iodide alkylation reactions showed diastereomeric ratios that moderate (81:19) to very good (96:4) with yields (86–98%). When LiCl was used as an enolate coordinating agent, benzylation propanoylated auxiliary a high crude ratio obtained (99.7:0.3).
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