Synthesis of 1-amino-2,2-dialkylcyclopropanecarboxylic acids from β-chloroaldimines
摘要:
A variety of hydrogen cyanide adducts of beta-chloroaldimines using acetone cyanohydrin were prepared. The reactive behaviour of these alpha-amino-gamma-chloronitriles towards bases was investigated with the aim to generate 1-aminocyclopropanecarbonitriles, which are precursors for the potentially plant growth regulating 1-aminocyclopropanecarboxylic acids. The synthesis of 1-amino-2,2-dimethylcyclopropanecarboxylic acid (= 2,3-methanovaline) by a reaction sequence involving addition of hydrogen cyanide across beta-chloroaldimines, ring closure to functionalized cyclopropanes and acidic hydrolysis was accomplished. Alternatively the hydrogen cyanide adducts of beta-chloroaldimines were converted into alpha-(N-benzylidene)amino-gamma-chloronitriles, which were ring closed with base and hydrolyzed to afford 1-amino-2,2-dialkylcyclopropanecarbonitriles, the latter serving again as substrates for the hydrolytic conversion into the corresponding 1-amino-2,2-dialkylcyclopropanecarboxylic acids (exemplified for 1-amino-2,2-dimethylcyclopropanecarboxylic acid).
Synthesis and reactivity of 3-(2-chloroalkyl)-2,2-dihaloaziridines
作者:Ekaterina Yu. Shinkevich、Kourosch Abbaspour Tehrani、Alexander F. Khlebnikov、Mikhail S. Novikov
DOI:10.1016/j.tet.2008.05.121
日期:2008.8
3-(2-Chloroalkyl)-2,2-dihaloaziridines were synthesized via cycloaddition of dihalocarbenes to the CN double bond of β-chloroimines. Under the action of Lewis acids or HCl, N–C3 bond cleavage occurred, giving rise to N-substituted 2,4-dichloro-3,3-dimethylbutanamides, which were further converted to 3-chloropyrrolidin-2-ones under alkaline conditions. When 2,2-dichloro-3-(2-chloro-1,1-dimethylethy
Rearrangement of 4-(1-Haloalkyl)- and 4-(2-Haloalkyl)-2-azetidinones into Methyl ω-Alkylaminopentenoates via Transient Aziridines and Azetidines
作者:Yves Dejaegher、Norbert De Kimpe
DOI:10.1021/jo040161b
日期:2004.9.1
The synthesis of 4-(1-haloalkyl)-2-azetidinones and 4-(2-haloalkyl)-2-azetidinones was investigated with use of the Staudinger reaction between in situ generated ketenes and alpha-haloimines or beta-haloimines. This new class of functionalized 2-azetidinones was further evaluated for its potential use as intermediates in the synthesis of highly functionalized compounds. The reaction of 4-(1-haloalkyl)-2-azetidinones and 4-(2-haloalkyl)-2-azetidinones with sodium methoxide in methanol yielded ring-opened products, i.e., methyl 2-alkoxy-4-(alkylamino)pentenoate and methyl 5-(alkylamino)pentenoate, respectively. Further attention was paid in detail to the reaction mechanism involved in this peculiar transformation. It was proven that these reactions proceeded via intermediate aziridines or azetidines.