Benzyl-2,2,2-trichloroacetimidate

Related Reagents. Benzyl Chloromethyl Sulfide r-Butyl Chloromethyl Ether 2-Chloroethyl Chloromethyl Ether Chloromethyl Methyl Ether Chloromethyl Methyl Sulfide (p-Methoxy-benzyloxy)methyl Chloride 2-Methoxyethoxymethyl Chloride 2-(Trimethylsilyl)ethoxymethyl Chloride. 

Raraformaldehyde can be used in place of formalin Gnedin-Vuong, D. Yoichi, N. BSF 1986, 245. 

Yamagishi, M. Yamada, Y Ozaki, K. Asao, M. Shimizu, R. Suzuki, M. Matsumoto, M. Matsuoka, Y Matsumoto, K. JMC1992,35,2085. 

Solubility reactions are most often carried out in a mixture of cyclohexane/dichloromethane decomposition by rearrangement to 7V-benzyl trichloroacetamide is accelerated in more polar solvents. 

The imidate can be prepared from the sodium alkoxide ion of benzyl alcohol and trichloroacetonitrile according to procedures based on those developed by Cramer in the late 1950s. Substituted benzyl ethers have also been prepared this way, for example using 4-methoxybenzyl trichloroacetimidate, 3,4-dimethoxybenzyl trichloroacetimidate, and 2,6-dichlorobenzyl trichloroacetimidate, and the method has also been applied for the synthesis of allyl and r-butyl ethers, as well as for 2-phenylisopropyl esters for peptide synthesis. The benzyl and 4-methoxybenzyl 2,2,2-trichloroacetimidates are available commercially. 

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Immobilized 38 also proved to be an appropriate glycosyl acceptor when coupled with a full benzylated trichloroacetimidate donor (Scheme 10.8). Thus, TMSOTf mediated coupling of 38 with an excess of 48 gave resin-bound 49, which was further coupled with acceptor 38 to give trisaccharide 60 (60% overall yield based loading of the resin). 

Dimethylthexylsilyl trifluorometh-anesulfonate, 74 using other methods Allyl chloroformate, 9 Benzyl trichloroacetimidate, 32 Bromodimethylborane, 47 Chloromethyl ethyl ether, 75 2,3-Dihydro-1,4-dioxin, 112 p-Methoxyphenol, 181 of aldehydes and ketones as acetals or dithioacetals... 

Cerium(IV) ammonium nitrate, 67 Dimethyl sulfate, 239 Other ethers Allyltrimethylsilane, 11 Benzyl trichloroacetimidate, 32 (E)-(Carboxyvinyl)trimethylammonium betaine, 67... 

Benzylation with benzyl trichloroacetimidate and a catalytic amount of triflic acid (TfOH) is a mild and efficient procedure (Scheme 2.1c).5 The acid protonates the nitrogen of the imidate moiety converting it into a very good leaving group. Nucleophilic attack by an alcohol introduces a benzyl ether. The procedure is often compatible with base- and acid-sensitive functionalities with esters, (7-isopropylidene and (7-benzylidene acetals. Benzyl trichloroacetimidate is commercially available but can easily be prepared by reaction of benzyl alcohol with trichloroacetonitrile in the presence of a mild base. 

Acid-Catalyzed Benzylation. Benzyl trichloroacetimidate, Cl3CC(=NH)OBn, reacts with hydroxyl groups under acid catalysis to give the con-esponding benzyl ethers in good yield. The method is particularly useful for the protection of base-sensitive substrates (i.e., alkoxide-sensitive), such as hydroxy esters or hydroxy lactones, as exemplified below. 

Etherification of the hydroxyl group at the C-3 position of 50 through benzylation using benzyl trichloroacetimidate under acidic conditions [57, 58] or an alkyl triflate under basic conditions gave 53 (42% (Et) and 17-90% (Bn) yields). Azide 53 was reduced to... 

The potential drawback to this preparation is the method for making 271. Standard conditions for alkylation of lactates using benzyl bromide and sodium hydride in DMF proceed in low yield and with some degree of racemization. Other alkylating reagents such as benzyl trichloroacetimidate, which does not lead to racemization, are rather expensive (see Section 1.4.2). 

Alkylation of dimethyl ( S)-malate (2) at oxygen can be accomplished with an alkyl halide in the presence of silver oxide. The methoxy derivative 7a forms in 74% yield [3], while the benzyloxy analog 7b is produced in 84% yield [12]. Alternatively, 7b can be prepared by treating 2 with (9-benzyl trichloroacetimidate in the presence of trifluoroacetic acid (68% yield) [13]. Upon treatment of malate ester 7a with barium hydroxide, (iS)-methoxysuccinic acid (8) is obtained in high yield [3]. 

H. S. Jensen, G. Limberg, and C. Pedersen, Benzylation of aldonolactones with benzyl trichloroacetimidate, Carbohydr. Res., 303 (1997) 109-112. 

When W-aceCyl-protected sugar amines were under investigation the A -acetyl group was observed to undergo transformation to the O-benzyl imidate in competition with OH benzylation (eq 3). It appears for best yields at least 1 equiv of reagent per OH and NAc group is needed, and subsequent hydrolysis and reacetylation of the amine are necessary to obtain are the originally desired material. Similar problems were encountered with the morpholine derived lactams (eq 4), where mixed products were obtained, but with p-lactams with yV-amide protection (eq 5), t -benzylation with benzyl trichloroacetimidate proceeded smoothly. BTCA has recently been used to convert diketopiperazines into their bis-benzyl imino ethers. ... 

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