A formyl group

When a formyl group (—CH=0) is attached to a nng the ring name is followed by the suffix carbaldehyde... 

In the Gatteinicin-Koch reaction, a formyl group (-CHO) is introduced directly onto a benzene ring. For example, reaction of toluene wjfh CO and HCJ in the presence of mixed CUCI/AICI3 gives p-methylbenzaldehyde. Propose a mechanism. 

When it s necessary to refer to the R-C=0 as a substituent, the name acyl (a-sil) group is used and the name ending -yl is attached. Thus, CFI3CO is an acetyl group, CHO is a formyl group, and C6H5CO is a benzoyl group. 

Acyl groups are common in bacterial polysaccharides. The parent acids are fatty acids, hydroxy acids, and amino acids. The simplest acid, formic acid, has only been found as the amide. The occurrence of O-formyl groups had been reported, but proved to be incorrect. A-Formyl groups have been found in different polysaccharides for example, in the 0-specific side-chains of the LPS from Yersinia enlerocolitica 0 9, which are composed of 4,6-dideoxy-4-formamido-D-mannopyranosyl residues. The formyl group can assume two main conformations, s-cis (41) and s-trans (42), which are... 

The absorption maxima of chlorophyll d, as expected, is very close to that of chlorophyll a, due to their structural similarity it has a formyl group instead of a vinyl group at C-3 but is otherwise identical with chlorophyll a. ... 

Many specific examples of these reactions can be found in reviews in the Organic Reactions series.65 Dichloromethyl ethers are also precursors of the formyl group via alkylation catalyzed by SnCl4 or TiCl4.66 The dichloromethyl group is hydrolyzed to a formyl group. 

The lower spectrum shows an ester group (triplet at 1.2 ppm, quartet at 4.2 ppm) and a singlet at 8.1 ppm, the latter indicating the presence of a formyl group. Peak 1 results from ethyl formate, formed by adventitious hydrolysis of the acetal 4. The middle and top spectra correspond to the two acetals (see equation) the assignment is very simple. 

Lemmtyinen and coworkers <01JPP835> have devised a protocol, in which the phytochlorin 37 containing a formyl group was transformed into glycine derivative 50 via reductive animation (Scheme 15). In the final step, derivative 50 was reacted with benzaldehyde and C6o, and gave rise to the phytochlorin C(,o diad 51. 

Nagasaki Y, Kutsuna T, Iijima M, Kato M, Kataoka K, Kitano S, Kadoma Y (1995) Formyl-ended heterobifunctional poly(ethylene oxide) synthesis of poly(ethylene oxide) with a formyl group at one end and a hydroxyl group at the other end. Bioconjug Chem 6 231-233... 

The very first report on the use of ionic liquids as soluble supports was presented by Fraga-Dubreuil and Bazureau in 2001 [102]. The efficacy of a microwave-induced solvent-free Knoevenagel condensation of a formyl group on the ionic liquid (IL) phase with malonate derivatives (E1CH2E2) catalyzed by 2 mol% of piperidine was studied (Scheme 7.89). The progress of the reaction could be easily monitored by 1H and 13C NMR spectroscopy, and the final products could be cleaved from the IL... 

Obata and Yamanishi106 employed several mild oxidizing agents, without success, in their attempts to oxidize the hydroxymethyl group of kojic acid to a formyl group. 

Branching at an olefinic carbon atom inhibited the reaction markedly, the most dramatic case being that of 2,3-dimethyl-2-butene. It should be noted that the product in this case is nearly exclusively 3,4-dimethylpen-taldehyde for either cobalt or rhodium catalysis (7). Thus, a general rule that products containing a formyl group attached to a quaternary carbon atom are not formed (49) remains valid. Hydroformylation proceeds only after isomerization has occurred. 

Again, addition of trialkylphosphine was found to be effective for reducing the amount of products obtained by attaching a formyl group to a carbon other than that of the original carbon-carbon double bond (73). Results obtained with hexenoic acid esters are outlined in Table XXIV. 

Under a pressure (20 bar) of carbon monoxide, carbonylative silylcarbocyclization of enyne 92 was examined in the presence of a cationic rhodium-BINAP catalyst (Scheme 31).86 Although the enantioselectivity is low, the five-membered carbocycle functionalized with an alkenylsilane moiety and a formyl group was obtained with high selectivity. 

Figure 10.15 The chlorophyll a and b molecules have vinyl, ethyl and phytyl side chains as R, R3 and R4, respectively chlorophyll a has a methyl group as R2, which is replaced by a formyl group in chlorophyll b. (From Voet and Voet, 2004. Reproduced with permission from John Wiley Sons., Inc.)...

The barrier to rotation of the cyclopentadienone hydrazone 37 is reported to be less than 11 kcal/mol (71). Introduction of a formyl group into the 2-position of the cyclopentadienylidene ring raised the barrier to 11.8 kcal/mol (71). 

Mazet et al. have reported an efficient asymmetric isomerization reaction of allylic alcohols [60, 61]. In a preliminary report they utilized the BArp analog of Crabtree s complex to efficiently catalyze a hydride transfer from the a position of the allylic alcohol to the p position of the olefin with a concomitant formation of a formyl group. A subsequent report detailed a remarkable enantioselective variant of this process catalyzed with Ir(12g) and (12h) (Scheme 12). 

In sharp contrast to the unique pattern for the incorporation of carbon monoxide into the 1,6-diyne 63, aldehyde 77 was obtained as the sole product in the rhodium-catalyzed reaction of 1,6-enyne 76 with a molar equivalent of Me2PhSiH under CO (Scheme 6.15, mode 1) [22]. This result can be explained by the stepwise insertion of the acetylenic and vinylic moieties into the Rh-Si bond, the formyl group being generated by the reductive elimination to afford 77. The fact that a formyl group can be introduced to the ole-finic moiety of 76 under mild conditions should be stressed, since enoxysilanes are isolated in the rhodium-catalyzed silylformylation of simple alkenes under forcing conditions. The 1,6-enyne 76 is used as a typical model for Pauson-Khand reactions (Scheme 6.15, mode 2) [23], whereas formation of the corresponding product was completely suppressed in the presence of a hydrosilane. The selective formation of 79 in the absence of CO (Scheme 6.15, mode 3) supports the stepwise insertion of the acetylenic and olefmic moieties in the same molecules into the Rh-Si bond. 

Radical cyclization of oximes or oxime ethers having allylic substituents or an aldehyde group to tetrahydropyrrole derivatives was described Thus, Sm -induced 5-exo-trig radical cyclization of oxime ethers containing a formyl group was found to be particularly effective for the preparation of cyclic trans-wimo alcohols. For example, oxime 96 in the system SmE/THF/f-BuOH at 25 °C or —78°C afforded pyrrolidin-3-ols 97 and 98 in a ratio 3 2 or 9 1 (equation 41) . Cyclization of oxime ether 99 in the... 

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