Aminohaloborane in Organic Synthesis. IV.¹ A Directed Aldol Condensation Using Vinylaminodichloroborane

Abstract

Continuing our studies on the specific ortho substitution reaction of anilines,² we tried to extend this methodology to directed aldol condensation^3. Namely, N-cyclohexylidencyclohexylamine 1 was treated with boron trichloride and triethylamine in dichloromethane giving N-cyclohexyl-N-1-cyclohexenylaminodi-chloroborane 2, to our knowledge, a new type of aminohaloborane. Similar treatment of N-2-butyliden-cyclohexylamine 3 gave N-cyclohexyl-N-2-butenylamino-dichloroborane (a mixture of E and Z isomers) 4. The physical data satisfied the assigned structures.