Efficient synthesis of isothiocyanates based on the tandem Staudinger/aza-Wittig reactions and mechanistic consideration of the tandem reactions.
The tandem and stepwise Staudinger/aza-Wittig reactions of several azides were examined in detail. The tandem reaction method (Method I) exhibited superior results in the yield of the corresponding isothiocyanates bearing an electron-withdrawing group than the conventional stepwise method (Method II) which involves the sequential treatment of the azides with triphenylphosphine and then carbondisulfide. The mechanistic consideration for both reaction methods was proposed on the basis of the 1H-NMR analyses.
Isoda
Takeshi
T
Medical Research Laboratories, Wyeth K K, Shiki, Saitama, Japan. isoda@konicaminolta.jp
Hayashi
Kazuhiko
K
Tamai
Satoshi
S
Kumagai
Toshio
T
Nagao
Yoshimitsu
Y
D001386:Azides / Q000138:chemical synthesis* / Q000737:chemistry; D017879:Isothiocyanates / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
D001386:Azides; D017879:Isothiocyanates