A general synthesis of substituted 1,2-dihydroisoquinolines based on intramolecular 1,3-dipolar cycloaddition of alkyl azides and olefins is described. Reaction of bromide 4 with sodium azide afforded azide 5, which underwent 1,3-dipolar cycloaddition intramolecularly to give triazoline 6. Rearrangement of triazoline 6 on silica gel gave diazo compound 7. Treatment of 7 with rhodium acetate afforded substituted 1,2-dihydroisoquinoline 9 in good overall yield.

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products observed in etherification of tertiary alkyl alcohols. Experimental Section12Typical Procedure for Preparation of Acyclic Ethers. To a stirred solution of -methylbenzyl alcohol (245 mg, 2.0 mmol) in dichloroethane (10 mL) at room temperature was added anhydrous zinc chloride (270 mg, 2.0 mmol). The reaction mixture was stirred at room temperature for 4 h, diluted with dichloromethane (30 mL), and washed with water and brine. The organic layer was dried over anhydrous MgS04 and evaporated to dryness.The residue was distilled with a Kugelrohr apparatus to afford bis ( -methylbenzyl) ether (206 mg, 91%) as a colorless oil. The spectral data and boiling point were identical with those of reported data.Typical Procedure for Preparation of Cyclic Ethers. To a stirred solution of 1-phenyl-1,5-pentanediol (182 mg, 1.0 mmol) in dichloroethane (20 mL) at room temperature was added zinc chloride (135 mg, 1.0 mmol), and the reaction mixture was stirred at 80 °C for 2.5 h. The usual workup and distillation with a Kugelrohr apparatus gave 2-phenyltetrahydropyran (136 mg, 84%). The spectral data13 and boiling point were in agreement with reported data.Acknowledgment. This investigation was supported in part by a grant from the Korea Science and Engineering Foundation. We are grateful to Sung Soo Kim for the experimental assistance.Registry No. PhCH(Me)OH, 98-85-1; Ph2CHOH, 91-01-0;

Das aus (Ia) bzw. (Ib) primär entstehende Azid (Ic) liefert über das nicht isolierte Triazolin‐Derivat (II) und weitere diskutierte Zwischenstufen die beiden Cyclisierungsprodukte (III) und (IV).