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A direct and catalyst-free method for the intramolecular aminoboration of unfunctionalized olefins is reported. In the presence of BCl3 (1 equiv) as the sole boron source, intramolecular aminoboration of sulfonamide derivatives of 4-penten-1-amines, 5-hexen-1-amines, and 2-allylanilines proceeded readily without the use of any catalyst. The boronic acids obtained after hydrolysis could be converted into the corresponding pinacol borates in a straightforward manner by treatment with pinacol under anhydrous conditions.

A general and practical method for the preparation of trans-2-substituted-4-halopiperidines and cis-2-substituted-4-halotetrahydropyrans is reported. Using 5 mol % of AlCl3 as the catalyst and 2 equiv of trimethylsilyl halides as the halide sources, aza-Prins cyclization of N-tosyl homoallylamine or Prins cyclization of homoallylic alcohol with carbonyl compounds could be readily realized, giving the corresponding trans-2-substituted-4-halopiperidines or cis-2-substituted-4-halotetrahydropyrans in high yields and satisfactory diastereoselectivity.

Trimethylsilyl bromide and chloride give the respective 5-bromo/chloro-methyl-2-aryloxazolines in similar yields.

A direct and catalyst-free method for the intramolecular aminoboration of unfunctionalized olefins is reported. In the presence of BCl3 (1 equiv) as the sole boron source, intramolecular aminoboration of sulfonamide derivatives of 4-penten-1-amines, 5-hexen-1-amines, and 2-allylanilines proceeded readily without the use of any catalyst. The boronic acids obtained after hydrolysis could be converted into the corresponding pinacol borates in a straightforward manner by treatment with pinacol under anhydrous conditions.

Aminohydroxylation product (IVb) can be carried out at gram-scale and the hydroxyl group can be further converted to a variety of different functional groups via conventional group transformation reactions such as azidation, bromination, acetylation, carboxylation and Swern oxidation.

BF3.Et2O is effective for both intra- and intermolecular hydroamination as well as for lactonization and esterification reactions of unactivated C=C double bonds.

A metal-free method for intramolecular halocyclization of unfunctionalized olefins was detailed. (Diacetoxyiodo)benzene (PIDA) was very effective for haloamidation, haloetherification, and halolactonization of unfunctionalized olefins. In the presence of 1.1 equiv of PIDA and suitable halogen sources, a variety of unfunctionalized olefins could be converted to the corresponding 1,2-bifunctional cyclic skeletons in good to excellent isolated yields, and key intermediates for biologically interesting compounds could be obtained in high yields under mild conditions via nucleophilic substitution of the thus obtained halocyclization products.

Trifluoroacetic acid was found to be effective in intramolecular hydroamination of unfunctionalized olefins bearing electron-rich amino groups, and the corresponding N-heterocycles were obtained in good isolated yields. The scope of the substrates was investigated, and a possible reaction mechanism was proposed. Substituents on C C double bonds and amino groups of the substrates showed drastic effects on the course of the reactions.

A facile synthesis of 3-halopiperidines and 2-halomethylpiperidines is achieved via iodine catalyzed intramolecular haloamination of amino substituted olefins.

The CuCl2 promoted cyclization of unsaturated amines at room temperature leads to the formation of intermediate pyrrolidine derivatives, which rearrange at elevated temperature to produce piperidines.

A new method for the intramolecular chloroamination of unfunctionalized olefins is reported. The reactions were carried out at room temperature for 3 h using hydrated copper(II) chloride as both promoter and chlorine source, and the corresponding vincinal haloamines were obtained in good isolated yields.

The investigation of the process under optimized catalysis reveals that steric and electronic factors play an important role in the formation of pyrrole structures bearing gem-substituents.