Hydride Reductions of 1-Phenyl-1-nonen-3 -one: Mass Spectrometry of 1-Phenyl-1-nonen-3-ols and Relative Stereochemistry of the Diastereoisomeric 4-Dimethylaminomethyl-1-Phenyl-1-nonen-3-ols

Abstract

The metal hydride reduction products of some styryl ketones and dimethylaminomethyl Mannich bases have been investigated. Sodium borohydride selectively attacked the carbonyl carbon atom to give the desired allylic alcohols. Reduction of 1-phenyl-1-nonen-3-one with lithium aluminum hydride gave 1-phenyl-3-nonanol which represents the conjugate addition product. Fragmentations of 1-phenyl-1-nonen-3-ol were compared to the modes of mass spectral breakdown of 4-phenyl-3-buten-2-ol, an allylic alcohol which is known to behave like a saturated ketone on electron bombardment. Peaks corresponding to the McLafferty ion and the loss of a methyl radical from this rearrangement product were observed. Certain Mannich bases were reduced to diastereoisomeric allylic amino alcohols. The separation, 1H n.m.r. spectroscopy, and relative stereochemistry of the diastereoisomers are discussed.