Stereoselective S(E)2' protonation of alpha-hydroxyallylsilanes mediated by a Brook rearrangement.
Brooked up! Treatment of (R,Z)-3-(tert-butyldimethylsilyl)-1-cyano-3-hydroxyprop-1-enyl carbamate with a catalytic amount of a base afforded (S,E)-3-(tert-butyldimethylsilyloxy)-1-cyanoallyl diisopropylcarbamate, showing that S(E)2'-type reaction of allylsilicates proceeds in an anti fashion. The overall process is equivalent to trapping of an enantioenriched C-chiral carbanion at the alpha-position of nitrile group in up to 77 % ee (see scheme).
Sasaki
Michiko
M
Graduate School of Medical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-Ku, Hiroshima, Japan.
Shirakawa
Yuri
Y
Kawahata
Masatoshi
M
Yamaguchi
Kentaro
K
Takeda
Kei
K
D002219:Carbamates / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
C540663:3-(tert-butyldimethylsilyl)-1-cyano-3-hydroxyprop-1-enyl carbamate; C540664:3-(tert-butyldimethylsilyloxy)-1-cyanoallyl diisopropylcarbamate; D002219:Carbamates; D017646:Organosilicon Compounds; D012821:Silanes