62134-69-4Relevant academic research and scientific papers
Electrophile-induced ring expansions of β-lactams toward γ-lactams
Van Brabandt, Willem,De Kimpe, Norbert
, p. 8717 - 8722 (2007/10/03)
An efficient and straightforward route toward 3,4-cis-4- isopropenylazetidin-2-ones was developed from 4-(1-chloroalkyl)azetidin-2-ones. Starting from the latter β-lactams, a new synthesis of pyrrolidin-2-ones was achieved. When 4-isopropenylazetidin-2-ones were treated with bromine in dichloromethane, diastereoselective electrophile-induced ring expansions toward 5-bromopyrrolidin-2-ones were performed. Further oxidation of 3-benzyloxypyrrolidin-2-ones with bromine toward 3-bromopyrrolidin-2-ones was also established. When 4-isopropenyl-β-lactams were added to a mixture of NBS and TMSN3, 5-azidopyrrolidin-2-ones were obtained in moderate to high yields.
Α-ARYLATION OF ALDEHYDES VIA Α-CHLOROALDIMINES
Kimpe, Norbert De,Zi-Peng, Yao,Schamp, Niceas
, p. 481 - 496 (2007/10/02)
α-Chloroaldimines are arylated at the α-position under Friedel-Crafts conditions via the presumptive intermediacy of α-imidoylcarbenium ions.Aluminium (III)chloride in arenes cleanly converted α-chloro-α-phenylaldimines into α-aryl-α-phenylaldimines.Aliphatic α-chloroaldimines could only be converted into the corresponding α-arylaldimines in low to moderate yields due to a lower reactivity and a competitive side reaction, i.e. dehydrochlorination into 1-aza-1,3-dienes. α-Bromo- and α-iodoaldimines were also evaluated under the given Friedel-Crafts conditions but the results appeared to be negative.The formation of all reaction products (i.e. α-arylaldimines, 1-aza-1,3-dienes and indolines) from the reaction of α-chloroaldimines with arenes in the presence of Lewis acids could be explained by the intermediacy of α-imidoylcarbenium ions, the chemistry of which is discussed to some extent.
Synthesis of Secondary Allylic Amines
Kimpe, Norbert de,Stanoeva, Elena,Verhe, Roland,Schamp, Niceas
, p. 587 - 592 (2007/10/02)
Secondary allylic amines were synthesized from aldehydes and primary amines via successive conversion into aldimines, α-haloaldimines and α,β-unsaturated aldimines, the latter being selectively reduced by sodium borohydride at the imino function.This method allowed the synthesis of secondary allylic amines with high preponderance of the E-stereochemistry.A comparison was made with an alternative method involving the generation of α,β-unsaturated aldimines from α,β-unsaturated aldehydes and primary amines, and subsequent borohydride reduction.
