Titanium chlorides, Reformatsky reactions

With Titanium [/F] Chloride. A novel type of Reformatsky reaction was reported [65] when ethyl 2-bromoethanoate was reacted with 2-acetoxytetra-hydrofuran derivatives and zinc, activated by the addition of 10% TiC in dichloromethane as the solvent. In the more common solvents such as benzene, toluene or XHF, yields were significantly lower. 

A novel Reformatsky reaction using ethyl bromoacetate-zinc-titanium tetrachloride has been applied with l-0-acetyl-2,3,5-tri-0-benzoyl-p-D-ribose to give the 3-linked product (159)." Compound (160), obtained by use of a Grignard reagent and a glycosyl chloride, has been made as a nucleoside analogue and incorporated into oligonucleotides for studies of duplex stability." ... 

Because they are even more nucleophilic than silyl enol ethers, silyl ke-tene acetals 58, derived from carboxylic esters, react vith ketones and aldehydes in the presence of titanium) IV) chloride to give j5-hydroxy esters 59 in high yields (Eq. (26)) [30, 31]. Although the Reformatsky reaction is vell kno vn as a good synthetic tool for synthesis of j5-hydroxy esters, the titanium) IV) chloride-mediated reaction is a milder and more versatile method for synthesis of a-substituted j5-hydroxy esters. 

Chromium carbene complexes, 82 Ethyl diazo(lithio)acetate, 230 Reformatsky reagent, 348 Titanium(IV) chloride, 304 By other reactions Di- p.-carbonylhexacarbonyldicobalt, 99... 

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