Elimination of water from the molecular ion of cycloheptanol
摘要:
AbstractUnder electron impact cycloheptanol decomposes by four fragmentation paths: (1) α‐cleavage with subsequent losses of C1‐C5 fragments, (2) elimination of water, (3) loss of the hydrogen atom from C‐1 and (4) loss of the hydroxyl group. The mechanism of water elimination was investigated by means of deuterium labelling. 1,4‐Elimination of water predominates in cycloheptanol, with the stereospecific cis‐1,3‐elimination also being operative. The loss of water is preceded by extensive exchange of the hydroxyl hydrogen with those of the ring. This is attributed to a very facile transannular interaction of the hydroxyl group with the C‐3 to C‐6 positions that are made accessible due to conformational properties of the 7‐membered ring. A kinetic model is proposed, describing migrations of the ring hydrogen atoms.