SYNTHESIS OF 1-ACETYL-INDOLINE-3-CARBINOL AND 1-ACETYLINDOLINE-3-ALDEHYDE .33. INTRAMOLECULAR AROMATIC ALKYLATIONS

Both racemic and enantiomeric 6 are reduced selectively by B2H6 yieldi ng the corresponding carbinols 1, while by treatment with LiAlH4 the 1 -ethyl derivatives 7 are formed. From 1 the halogen compounds 2 can be prepared. Direct transformations of 6 or 15a,b to the title compound 3 fail. Hydrogenation of the aldehyde 8 gives mainly the hydrogenolysi s product 9 besides little amounts of 1. Depending from catalyst the a cetals 10 and 12 can be hydrogenated to the indolines 11 and 13; using Rh-catalyst 12 is also hydrogenolised partially to the ether 14. In c ontrast to 11 acetal 13 can be cleaved by BBr3/-78 degrees C leading t o the unstable aldehyde 3 in moderate yield.