A new synthetic method for functionalized cyclopentanones was developed on the basis of a [3+2] cycloaddition reaction of a 1-(methylthio)-2-siloxyallyl cationic species and olefins. Allyl acetates 1a and 1b, which are the precursors of the allyl cationic species, are easily prepared in three or four steps from commercially available compounds. Under the influence of EtAlCl2 or AlCl3, 1a or 1b reacted
Facile Synthesis of trans-S-1-Propenyl-L-Cysteine Sulfoxide (Isoalliin) in Onions (Allium cepa)
作者:Sang-Ku Lee、Jae-Nyoung Kim、Dong-Ho Choung、Hyeong-Kyu Lee
DOI:10.5012/bkcs.2011.32.1.319
日期:2011.1.20
(E)-1-(benzylthio)-1-propen (3) (Scheme 1). The isomerically pure trans-(1-propen) compound 3 was obtained providing the characteristic large NMR coupling of the trans-olefinic protons (J = 15.0 Hz). Reductive cleavage of a C-S bond in compound 3 by Na in liquid NH3 followed by addition of 3-chloro-L-alanine hydrochloride gave trans-S-1-propenyl-L-cystein (4). Finally, the oxidation of sulfide 4 by aqueous hydrogen