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Asymmetric Sequential Michael Addition– N –Heterocyclization Reactions Involving Chiral Imines
Author(s) -
D'angelo Jean,
Cavé Christian,
Desmaële Didier
Publication year - 1997
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199700010
Subject(s) - chemistry , imine , maleic anhydride , adduct , pyrrole , organic chemistry , derivative (finance) , bicyclic molecule , medicinal chemistry , catalysis , copolymer , economics , financial economics , polymer
The reaction of chiral imines ent ‐ 14, 27 , and 31 with α‐chloroacrylonitrile 6 , maleic anhydride 9 , and citraconic anhydride 35 has been investigated. Addition of imine 27 to 6 furnished, after NaBH 3 CN‐reduction of the crude product, the bicyclic derivative 28 as a single isomer. When the same protocol was applied to imine ent ‐ 14 , a mixture of adducts 29 and 30 was obtained. Addition of imine 31 to 6 gave the annulated pyrrole 32. Condensation of imine 27 with maleic anhydride 9 afforded compound 33 as a single isomer. Addition of imine ent ‐ 14 to citraconic anhydride 35 led, after esterification of the crude product with CH 2 N 2 , to a mixture of adducts 36 and 37. The mechanism of these aza‐annulations was discussed on the basis of the regio‐ and stereoselectivities observed.