Highly stereoselective indium trichloride-catalysed asymmetric aldol reaction of formaldehyde and a glucose-derived silyl enol ether in water

Indium Trichloride-Catalyzed Conjugate Addition of Amines to α,β-Ethylenic Compounds in Water

“…Organic reactions in water or aqueous media have recently attracted great interest. 8,9 Recently, we have reported indium trichloride as an excellent catalyst in the Mukaiyama aldol reactions, [10][11][12] Diels-Alder reactions, 13 aldol-type Mannich reaction 14 and Michael reaction 15 neat or in water under mild conditions. As indium trichloride has these unique properties compared to other Lewis acids which include stability and recoverability from water, we are interested to apply it to other carbon-carbon bond formation reactions in water.…”

Discovery of indium complexes as water-tolerant Lewis acids

“…This method uses the commercially available formaldehyde with InCl 3 as catalyst, giving good yields and excellent selectivities (Table 8). 25 Note that both cis and trans isomer of the silyl enol ether gave the same major isomer. The formaldehyde nucleophile was proposed to approach only in one direction due to the steric restrictions imposed by the rigid silyl enol ether.…”

Aldol Reaction—Homogeneous

“…The stereoselective Mukaiyama aldol reaction was further reported by Loh and co-workers in 1998. The asymmetric indium-catalyzed Mukaiyama aldol reaction of silyl enol ester derived from diacetone D-glucose gave a corresponding product in good yield and enantioselectivity (96:4 enantiomeric ratio) (Scheme 41) (170). As a supplement in the InCl 3 -catalyzed asymmetric Mukaiyama aldol reaction, Loh and co-workers extended the glucose-based chiral reagent to a keto ester containing a chiral amino ester backbone in the Mukaiyama aldol reaction (171).…”