Sulfoxide, chloromethyl phenyl butyllithium

Durst reported that lithiation of chloromethyl phenyl sulfoxide (99) with butyllithium followed by treatment of a symmetrical ketone (-78 °C to -20 C) affords an adduct (100). This reaction is so highly stereoselective that only one diastereomer is produced. Reaction of (100) with dilute methanolic KOH gives an epoxy sulfoxide (101 equation 25). - °... 

A soln. of chloromethyl phenyl sulfoxide in tetrahydrofuran allowed to react at -78° with -butyllithium, then with cyclohexanone at -78° for 10 min. and at -20° for 0.5 hr. -> adduct (Y 79%) treated 10 min. at room temp, with dil. methanolic KOH -> a-epoxy sulfoxide (Y > 90%). - Formation of the adduct is highly stereospecific. The ease of intramolecular displacement of chloride ion from the adduct contrasts with the great difficulty in displacing chloride ion from chloromethyl phenyl sulfoxide by external nucleophiles. F. e. s. T. Durst, Am. Soc. 91, 1034 (1969) a-chloro-a-lithiumsulfonic acid derivatives s. W. E. Truce and L. W. Christensen, Tetrah. Let. 1969, 3075 syntheses with dichloromethyllithium s. G. Kobrich and W. Werner, Tetrah. Let. 1969, 2181. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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