
TY  - JOUR
A1  - Mander, LN 
A1  - Turner, JV 
T1  - Studies on intramolecular alkylation. XII. Stereochemical aspects of the preparation of &#946;,&#947;-unsaturated aldehydes from the [2,3]-sigmatropic rearrangement of ammonium ylides
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1980
VL  - 33
IS  - 7
SP  - 1559
EP  - 1568
KW  - 
UR  - https://doi.org/10.1071/CH9801559 
N2  - The [2,3]-sigmatropic rearrangement of a series of acetonitrile-derived allylic ammonium ylides [RCH2N+ (C4H8)-CHCN; R = 4'-t- butylcyclohexylidenemethyl (3), 4'-t-butylcyclohex-1-enyl (10), 5'-t- butyl-2'-methylcyclohex-1-enyl (14), 4'-t-butyl-2'-methylcyclohex-1- enyl (20)], followed by acid-catalysed hydrolysis in each case, furnished an excellent yield of a diastereomeric pair of &#946;,&#947;-olefinic aldehydes [(5)/(6), (12)/(13), (15)/(16) and (21)/(22)]. With cyclohexylidene ylide (4) addition of the carbanion to the more exposed (equatorial vector) face is strongly preferred. In the cyclohexenyl examples there is a clear stereoelectronic requirement in opposition to steric forces which leads mainly to axial carbon-carbon bond formation. 
ER  -

