Synthesis of α-chloroketones and α-chloroaldehydes

Recent Literature

Aliphatic and aromatic ketones can be directly converted into their corresponding α-chloroketone acetals in very good yields using iodobenzene dichloride in ethylene glycol in the presence of 4 Å molecular sieves at room temperature.
J. Yu, C. Zhang, Synthesis, 2009, 2324-2328.

A fluorous (S)-pyrrolidine-thiourea bifunctional organocatalyst shows good activity and enantioselectivity for direct α-chlorination of aldehydes using N-chlorosuccinimide (NCS) as the chlorine source. The catalyst can be recovered from the reaction mixture by fluorous solid-phase extraction with excellent purity for direct reuse.
L. Wang, C. Cai, D. P. Curran, W. Zhang, Synlett, 2010, 433-436.

A direct organocatalytic enantioselective α-chlorination of aldehydes proceeds for a series of different aldehydes with NCS as the chlorine source using easily available catalysts such as L-proline amide and (2R,5R)-diphenylpyrrolidine. The α-chloro aldehydes are obtained in very good yield and high enantioselectivity.
N. Halland, A. Braunton, S. Bachmann, M. Marigo, K. A. Jorgensen, J. Am. Chem. Soc., 2004, 126, 4790-4791.

The use of enamine catalysis has provided a new organocatalytic strategy for the enantioselective chlorination of aldehydes to generate α-chloro aldehydes, an important chiral synthon for chemical and medicinal agent synthesis.
M. P. Brochu, S. P. Brown, D. W. C. MacMillan, J. Am. Chem. Soc., 2004, 126, 4108-4109.

Catalytic enantioselective fluorination and chlorination reactions of carbonyl compounds were achieved with high enantioselectivity by the use of a dbfox-Ni^II complex.
N. Shibata, J. Kohno, K. Takai, T. Ishimaru, S. Nakamura, T. Toru, S. Kanemasa, Angew. Chem. Int. Ed., 2005, 44, 4204-4207.

The regio- and stereoselective aminochlorination of α,β-unsaturated ketones with N,N-dichloro-p-toluenesulfonamide (4-TsNCl₂) and CuOTf as catalyst provides an easy access to vicinal haloamino ketones, with excellent regioselectivity and good yields. Aromatic and aliphatic enones give opposite regioselectivity.
D. Chen, C. Timmons, S. Chao, G. Li, Eur. J. Org. Chem., 2004, 3097-3101.

Poly{[4-(hydroxy)(tosyloxy)iodo]styrene} was efficient in the halotosyloxylation reaction of alkynes with iodine or NBS or NCS. The polymer reagent could be regenerated and reused.
J.-M. Chen, X. Huang, Synthesis, 2004, 1557-1558.

Efficient oxidative α-halogenation of 1,3-dicarbonyl compounds has been achieved by employing a system comprising of sub-stoichiometric amounts of TiX₄ (X = Cl, Br) in the presence of environmentally benign hydrogen peroxide (H₂O₂) or peracetic acid (MeCO₃H) as the oxidants. The end point of the reaction is accompanied by a sharp colour change.
R. Akula, M. J. Galligan, H. Ibrahim, Synthesis, 2011, 347-351.