Dibromomethane-Zinc-Titanium Chloride

Related Reagents. Dibromomethane-Zinc-Titanium(IV) Chloride Methylenetriphenylphosphorane. 

Related Reagents. Dibromomethane-Zinc-Titanium(IV) Chloride Diiodomethane-Zinc-Titanium(IV) Chloride 4R, 5i )-2,2-Dimethyl-4,5-bis(hydroxydiphenylmethyl)-l,3-di-oxolane-Titanium(IV) Chloride Lithium Aluminum Hydride-Titanium(IV) Chloride Titanium(IV) Chloride-Diazabicyclo-[5.4.0]undec-7-ene Titanium(IV) Chloride-2,2,6,6-Tetramethyl-piperidine Titanium(IV) Chloride-Triethylaluminum Titanium-(IV) Chloride-Zinc. 

Several modifications of the Simmons-Smith procedure have been developed in which an electrophile or Lewis acid is included. Inclusion of acetyl chloride accelerates the reaction and permits the use of dibromomethane.174 Titanium tetrachloride has similar effects in the reactions of unfunctionalized alkenes.175 Reactivity can be enhanced by inclusion of a small amount of trimethylsilyl chloride.176 The Simmons-Smith reaction has also been found to be sensitive to the purity of the zinc used. Electrolytically prepared zinc is much more reactive than zinc prepared by metallurgic smelting, and this has been traced to small amounts of lead in the latter material. 

Lombardo methylenation (zinc-dibromomethane-titanium tetrachloride) of methyl 2-deoxy-5-0-(4-phenylbenzoyl)-P-D-g/ycero-pent-3-uloside, followed by dihydroxylation, gave the 3-C-hydroxymethyl derivative 7 (R = 4-phenylbenzoyl) exclusively. A ran of other 2-deoxypentuloses was also subjected to a similar course of reactions, but erally resulted in the formation of epimers during the dihydroxylation step. The hydroxymethyl group was further transformed first with tosyl chloride to the tosylate which was displaced with adenine or thymine to yield nucleoside analogues. ... 

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