A simple and efficient synthesis of new dihydrospiro[(1H)quinoline-2,1 '-cyclohexane] derivatives via internal Friedel-Crafts alkene alkylation of N-(1-allylcyclohexanyl)ethylphenylamine

New substituted dihydrospiro[(1H)quinoline-2,1'-cyclohexanes] were prepared by the internal alkene alkylation of N-(1 -allylcyclohexanyl) ethylphenylamine obtained from the- corresponding ketimine and allylmagnesium bromide. The I-allyl-6ethyl -4-methyl-3,4-dihydrospiro[(1H)quinoline-2, 1'-cyclohexane] undergoes an amino-Claisen transposition (BF3 - Et2O) to afford the 8-allyl-6-ethyl-4-methyl substituted spiroquinolines or a second internal alkylation reaction promoted by Bronsted acid (H2SO4) to give a new unnatural lilolidine spiroderivative.