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Asymmetric Sulfinylations of N ‐Methylephedrine‐Modified Tri‐ or Tetraalkyl Zincates by Symmetric Diaryl Sulfoxides
Author(s) -
Ruppenthal Simon,
Brückner Reinhard
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201701603
Subject(s) - chemistry , reagent , diethylzinc , alkyl , alkoxide , enantiomeric excess , aryl , enantioselective synthesis , yield (engineering) , enantiomer , medicinal chemistry , organic chemistry , sulfoxide , catalysis , materials science , metallurgy
Diethylzinc was treated with 1 or 2 equiv. of AlkMgCl or PhMgBr (preferably) or with 1 equiv. of n BuLi (less efficiently) for forming species – plausibly zincates – which were sulfinylated by diaryl sulfoxides to give racemic alkyl aryl sulfoxides in yields reaching 100 %. Dialkylzinc reagents were also activated by treatments with 1 or 2 equiv. of an enantiomerically pure alkylmagnesium β‐aminoalkoxide. This worked best when the alkoxide stemmed from a dialkylmagnesium reagent and an equimolar amount of N ‐methyl‐(–)‐ephedrine. This second activation mode allowed sulfinylations of what was originally the dialkylzinc reagent with diaryl sulfoxides. This generated alkyl aryl sulfoxides with enantiomeric ratios up to 93:7 in up to 100 % yield.