Preparation of optionally substituted dihydroisoquinolines

A process for preparing a compound of formula I,

• wherein
• R3, R4 are independently selected from C1-C6-alkyl, C2-C6-alkenyl, C2-C6-alkynyl, C1-C6-halogenalkyl, C2-C6-halogenalkenyl and C2-C6-halogenalkynl;
• R78 is independently selected from halogen, C1-C6-alkyl, C1-C6-alkoxy, C1-C6-halogenalkyl and C1-C6-halogenalkoxy;
• o is 0, 1, 2 or 3;
• Y is selected from C1-C6-alkyl, C1-C6-halogenalkyl, phenyl and benzyl, wherein phenyl and benzyl are unsubstituted or substituted by CN, NO2, halogen, C1-C6-halogenalkyl or C1-C6-alkoxy.
• comprising one step reaction of a compound of the formula II
• wherein R3, R4, o and R78 are as defined above with a compound of formula III
• wherein Y is as defined above.