Takai-Utimoto reaction

The Takai-Utimoto reaction of alkyl halides 360 with aldehydes 361 is a convenient method for the synthesis of branched alcohols 363 with high functional group tolerance [455]. Vitamin B12 362 or cobalt phthalocyanine served as the catalyst and CrCl2 as the stoichiometric reducing agent (Fig. 99). The reactions proceeded well with aromatic and aliphatic aldehydes. 

Fig. 99 Original cobalt-catalyzed chromium-mediated Takai-Utimoto reactions...

Fig. 100 Takai-Utimoto reactions catalytic in cobalt and chromium...

Boeckman, R. K., Jr., Hudack, R. A. A Variant of the Takai-Utimoto Reaction of Acrolein Acetals with Aldehydes Catalytic in Chromium A Highly Stereoselective Route to Anti Diol Derivatives. J. Org. Chem. 1998, 63, 3524-3525. 

Related reactions Horner-Wadsworth-Emmons oiefination, Julia oiefination, Peterson oiefination, Takai-Utimoto oiefination, Tebbe... 

Peterson olefination, Takai-Utimoto olefination, Tebbe olefination, Wittig reaction, Wittig reaction - Schlosser modification ... 

Indolylvinyl iodides III-55 and III-56 were synthesized using the Takai-Utimoto olefination [160], starting from the corresponding aldehydes, in moderate to high yields (Scheme 4.33). Unfortunately, when we tried this reaction cataly-Mc, only traces of the iodides were detected [161]. 

For examples of this coupling reaction involving enol triflates derived from ketones, see Takai, K. Taga-shira, M. Kuroda, T. Oshima, K. Utimoto, K. Nozaki, H. J. Am. Chem. Soc. 1986, 108, 6048. 

K. Takai, K. Sakogawa, Y. Kataoka, K. Oshima, and K. Utimoto 180 PREPARATION AND REACTIONS OF ALKENYLCHROMIUM REAGENTS 2-HEXYL-5-PHENYL-1-PENTEN-3-OL... 

A variation of this reaction was developed in 1986 by Takai and Utimoto, in which geminal dihaloalkanes were added to aldehydes in a reaction mediated by chromium dichloride. This led to the stereoselective formation of the corresponding tran5-olefins 10 [12]. The major drawback of this method is the rather cumbersome access to the corresponding substituted dihalomethane compounds, which prevents a broad application of this reaction for synthesis. 

Okazoe, T Takai, K. Oshima, K. Utimoto, K. J. Org. Chem. 1987, 52, 4410. For the reaction with CH2(ZnI)2 with TiCl2, see Matsubra, S. Ukai, K. Mizuno, T Utimoto, K. Chem. Lett. 1999, 825. This procedure is also successful for silyl esters, to give silyl enol ethers Takai, K. Kataoka, Y Okazoe, T Utimoto, K. Tetrahedron Lett. 1988, 29, 1065. 

Takai K, Tagashira M, Kuroda T, Oshima K, Utimoto K, Nozaki H (1986) Reactions of Alkenylchromium Reagents Prepared from Alkenyl Tiifluoromethanesulfonates (Triflates) with Chromium(n) Chloride under Nickel Catalysis. J Am Chem Soc 108 6048... 

Takai and Utimoto showed that reactions of aldehydes and a gem-diiodoalkane with chromium(II) chloride gave Wittig-type olefination products (Scheme 5.25) [35]. The notable points of this transformation are stereoselective ( )-alkene formation and chemoselective reaction with the aldehyde. Ketones are recovered unchanged. Instead of a gem-diiodoalkane, a-acetoxy bromide can also be used for this transformation [36]. 

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