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Desymmetrization of meso‐N‐ Sulfonylaziridines with Chiral Nonracemic Nucleophiles and Bases
Author(s) -
Müller Paul,
Nury Patrice
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20010321)84:3<662::aid-hlca662>3.0.co;2-p
Subject(s) - chemistry , aziridine , desymmetrization , carbenoid , allylic rearrangement , bicyclic molecule , medicinal chemistry , umpolung , lewis acids and bases , nucleophile , yield (engineering) , organic chemistry , catalysis , stereochemistry , enantioselective synthesis , ring (chemistry) , rhodium , materials science , metallurgy
The cyclohexene‐derived aziridine 7‐tosyl‐7‐azabicyclo[4.1.0]heptane ( 1 ) reacts with Grignard reagents in the presence of chiral nonracemic Cu‐catalysts to afford sulfonamides 3a – e ( Scheme 3 ) in up to 91% ee under optimized conditions ( Table 2 ). No activation of the aziridine by Lewis acids is required. The reaction may be extended to other bicyclic N ‐sulfonylated aziridines, but aziridines derived from acyclic olefins, cyclooctene, and trinorbornene are unreactive under standard conditions ( Scheme 5 ). Exposure of 1 to s ‐BuLi in the presence of (−)‐sparteine (2.8 equiv.) affords the allylic sulfonamide 31 in 35% yield and 39% ee ( Scheme 6 ). Under the same conditions, the aziridines 33 and 35 yield products 34 and 36 derived from intramolecular carbenoid insertion with 75 and 43% ee, respectively.