Dichloromethyl methyl ether formylation with

Besides 11-15-11-17, several other formylation methods are known. In one of these, dichloromethyl methyl ether formylates aromatic rings with Friedel-Crafts catalysts.The Compound ArCHClOMe is probably an intermediate. Orthoformates have also been used. In another method, aromatic rings are formylated with... 

Besides 1-15 to 1-17, several other formylation methods are known.302 In one of these, dichloromethyl methyl ether formylates aromatic rings with Friedel-Crafts catalysts.303 ArCHClOMe is probably an intermediate. Orthoformates have also been used.304 In another method, aromatic rings are formylated with formyl fluoride HCOF and BF3.305 Unlike formyl chloride, formyl fluoride is stable enough for this purpose. This reaction was successful for benzene, alkylbenzenes, PhCl, PhBr, and naphthalene. Phenols can be regioselectively formylated in the ortho position in high yields by treatment with two equivalents of paraformaldehyde in aprotic solvents in the presence of SnCL and a tertiary amine.306 Phenols... 

Frontier orbital theory predicts that electrophilic substitution of pyrroles with soft electrophiles will be frontier controlled and occur at the 2-position, whereas electrophilic substitution with hard electrophiles will be charge controlled and occur at the 3-position. These predictions may be illustrated by the substitution behaviour of 1-benzenesulfonylpyr-role. Nitration and Friedel-Crafts acylation of this substrate occurs at the 3-position, whereas the softer electrophiles generated in the Mannich reaction (R2N=CH2), in formylation under Vilsmeier conditions (R2N=CHC1) or in formylation with dichloromethyl methyl ether and aluminum chloride (MeO=CHCl) effect substitution mainly in the 2-position (81TL4899, 81TL4901). Formylation of 2-methoxycarbonyl-l-methylpyrrole with... 

Several chlorophyll derivatives have been prepared by electrophilic substitution, inter alia by formylation reactions. Adopting methods from corrin chemistry.50 alkylation with chloro-methyl methyl ether (caution toxic),32k chloromethyl methyl sulfide,51 and dichloromethyl methyl ether (caution toxic)52 in the presence of Lewis acids are the methods of choice to introduce carbon residues into the chlorin frame work. The compounds listed below have been prepared by these methods. 

Formylation of 2-methoxycarbonyl-l-methylpyrrole with dichloromethyl methyl ether and aluminum chloride occurs in the 4-position, while under Vilsmeier conditions the main product is the 5-formyl derivative (78JOC4849). 

Acetylation and formylation are classical reactions in porphyrin chemistry. H. Fischer s synthesis of hemin, for which he was awarded the 1930 Nobel prize, required treatment of deuterohemin (49) with acetic anhydride (or acetyl chloride) in the presence of tin(IV) chloride as a Friedel-Crafts catalyst the product, 3,8-diacetyldeuterohemin-IX (50), was obtained in high yield. Fischer also accomplished formylation of iron porphyrins using dichloromethyl methyl ether and a Friedel-Crafts catalyst (B-37MI30700). Both of Fischer s examples resulted in peripheral substitution of unsubstituted iron porphyrins. However,... 

The synthesis was performed according to Scheme 9.3. 1,2-Bis (2-methyl-1-ben-zothiophen-3-yl)perfluorocyclopentene (9a) was formylated with dichloromethyl methyl ether to give diformyl compound 14, which treated with 2,3-bis(hydroxy-amino)-2,3-dimethylbutane sulfate followed by sodium periodate. Compound 10a was obtained and purified by column chromatography and gel permeation chromatography (GPC). Recrystallization from hexane-CH2Cl2 gave dark-blue plate crystals of 10a. 

Nitration and FriedelCrafts acylation of 1-phenylsulfonylpyrrole occur at the 3-position, whereas the softer electrophiles generated in the Mannich reaction (R2N+=CH2), in formylation under Vilsmeier conditions (R2N+=CHC1) or in formylation with dichloromethyl methyl ether and aluminum chloride (MeO+=CHCl), effect substitution mainly in the 2-position. 

Formylation of unsaturated silanes. a, -Unsaturated aldehydes can be prepared by reaction of vinylsilanes with dichloromethyl methyl ether in the presence of 1 equiv. of TiCl, (equation 1). The enals have the (E)-conflguration, regardless of... 

Formylation of heteroeycies with dichloromethyl methyl ether 78ZC201. 

Introduction of a formyl group at C3 on methyl ethers can be performed by direct treatment with dichloromethyl methyl ether under titanium tetrachloride catalysis (82CJC2821), as in the conversion of 153 into 154 or by modification of the side chain of pyrone 2, including an oxidation step on methyl ether 156, to afford 157 (87TL1175). 3-Formyl-4-hydroxy-6-methyl-... 

Methoxy-4-methoxycarbonyoxytoluene at 0°C in dichloromethane upon treatment with titanium tetrachloride and then dichloromethyl methyl ether both in CH2CI2 over 30mins. by stirring for a few mins, with hydrochloric acid gave 6-formyl-4-methoxy-5-methoxycarbonyloxy-2-methylbenzaldehyde in 97% yield (ref.92). 

Disubstituted pyrroles lacking substituents at the 3- and S-positions are often required in porphyrin synthesis, and these can now be prepared from pyrrole itself. Thus, trichloroacetylation or trifluoroacetylation of pyrrole affords the 2-trihaloacetylpyrrole 8, which can be converted into the corresponding esters 9, carboxylic acids, or amides. The amides have been acetylated, or formylated, at the 4-position specifically, and the resulting acyl pyrroles (10) have been reduced to the alkyl pyrroles (11). This general procedure has now been improved by direct Friedel-Crafts formylation of the trichloroacetylpyrrole (8a) with dichloromethyl methyl ether (aluminium chloride) to the diacylpyrroles... 

Yamato and co-workers introduced dichloromethyl methyl ether in the presence of titanium tetrachloride as a reagent for one-pot formylation followed by in situ Bradsher cyclization. In this way anthracene regioisomers 25 and 26 were obtained from diaryImethane 24 in good yield. The initially formed anthracene derivative presumably reacts with excess dichloromethyl methyl ether to yield 9- or 10-formylanthracene derivative 25 or 26. 

Dichloromethyl methyl ether, a potential formylating agent with hi er electrophilicity, had been reported to give only 2 1 products with alkenes. This result can be explained by concentration control, since... 

Acetylbenzo[6]tellurophene is also formed in isolable quantities. Benzo[6]selenophene is converted into 2-acyl derivatives by reaction with acid chlorides in the presence of aluminum chloride, whereas similar Friedel-Crafts acylation of benzo[6]thiophene yields 3-substituted products. When the 2-position is blocked, formylation can be directed into the 3-position. Thus treatment of 2-bromobenzo[6]selenophene with dichloromethyl butyl ether (Cl2CHOBu) and titanium tetrachloride yields the 3-formyl derivative (72BSF3955). If the 2- and 3-positions of benzo[6]selenophene are blocked with methyl groups, acylation under Friedel-Crafts conditions occurs in the 6-position (78CR(C)(287)333>. 

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