2- Iodomethyl-l,3-dioxolane

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) cis-4-Hydroxymethyl-2-iodomethyl-l,3-dioxolane [61508-55-2]... 

Alkylation of a-lithio-iV,/V-dimethylhydrazones with 2-(iodomethyl)-l,3-dioxolane provides masked 7-hydrazonoaldehydes. Cyclization occurs after acid-catalyzed removal of the dioxolane protecting group and the /V-unsubstituted pyrrole can be obtained by hydrogenolysis of the N,N-dimethylamino substituent (Scheme 41) (88JHC1135). 

A soln. of acetophenone dimethylhydrazone in HMPT slowly added to a stirred soln. of LiN(Pr-/)2 in THE at — 20°, after 2 h the mixture warmed to 0°, stirred for a further 2 h, cooled to —78°, 2-iodomethyl-l,3-dioxolane added slowly, after 1 h the mixture warmed slowly to room temp., and worked up after 12 h - intermediate (Y 95%), in toluene containing -TsOH refluxed for 30 h - l-dimethylamino-2-phenylpyrrole (Y 90%), suspended in 3 1 MeOH/H20, and hydrogenated with Raney nickel at room temp, under 60 p.s.i. H2 for 48 h - 2-phenylpyrrole (Y 85%). F.e.s. G. Chelucci, M. Marchetti, J. Heterocyc. Chem. 25, 1135-7 (1988). 

An approach to the preparation of chiral 208 utilizes a free-radical chain-elongation reaction for the preparation of 206. Alcohol 141 is converted in two steps and 92% yield to (4iS, 5R)-4-benzyloxymethyl-5-iodomethyl-2,2-dimethyl-l,3-dioxolane (209). Treatment of... 

Dioxane reacts with trimethylsilyl iodide 17 to give 96% 1,2-bis-iodoethane, 53% l,2-bis(trimethylsilyloxy)ethane, and 32% HMDSO 7 ]5, 29]. 1,3-Dioxolane 840 furnishes, via 841, iodomethyl-2-iodoethyl ether 842 and HMDSO 7 ]5, 30] (Scheme 6.13). 2-Substituted 1,3-dioxolanes 843 are converted by trimethylsilyl iodide 17, via a series of postulated intermediates, into 1,2-diiodoethane, the ester 844, the alkyl iodide 845, and HMDSO 7 [5] (cf also Chapter 5, Scheme 5.67). 

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