Preparation of hydroindane and its derivative

PURPOSE: To obtain the compds. in excellent yield, which are a synthesizing raw material for vitamin D compd. or a synthetic intermediate by selectively oxidizing a compd. having terminal isopropyl group corresponding to the objective compds. with dioxirane, etc., as oxydant. CONSTITUTION: The compds. of the formula I [where R 5 is methyl, ethyl, fluorinated ethyl or the like; R 3 has terminal isopropyl and (substd.)alkyl or alkoxy; Y is (protected)hydroxymethylene; R 2 forms ring with H, Y together with the adjacent C] are oxidized by once oxidation, selective oxidation of terminal isopropyl group, to produce the compds. (e.g. the compd. of the formula III, or the like) of the formula II (R is methyl, ethyl, fluorinated ethyl, formyl or the like; R 1 is terminal 2-hydroxyprop-2-yl or the like; Z is carbonyl, protected hydroxymethylene, or forms ring Z and R 2 together with adjacent C). As the oxydants, dimethyl dioxirane, methyl (trifluoromethyl)dioxirane, bis(trifluoromethyl)dioxirane are especially suitable. COPYRIGHT: (C)1994,JPO