Nucleophile functional group

Several other nucleophilic functional groups can be induced to participate in iodocyclization reactions. t-Butyl carbonate esters cyclize to diol carbonates.79... 

Other nucleophilic functional groups can participate in iodocyclization. Amides usually react at oxygen, generating imino lactones that are hydrolyzed to lactones.88... 

Compounds in which a carbonyl or other nucleophilic functional group is close to a carbenoid carbon can react to give ylide intermediate.221 One example is the formation of carbonyl ylides that go on to react by 1,3-dipolar addition. Both intramolecular and intermolecular cycloadditions have been observed. 

Generally speaking imidazole is the nucleophilic functional group, and many of the chiral surfactants are histidine derivatives (Brown and Bunton, 1974 Brown et al., 1981). In other cases mixed systems have been used, e.g. an inert cationic surfactant plus a chiral amphiphilic histidine or hydroxa-... 

As shown in Figure 4.1, the initial step of the conversion of an ylide into a carbene complex is an electrophilic attack at the ylide. Reactions of this type will, therefore, occur more readily with increasing nucleophilicity of the ylide and increasing electrophilicity of the metal complex L M. Complexes which efficiently catalyze the decomposition of even weakly nucleophilic ylides can easily react with other nucleophiles also, such as amines or thiols. This has to be taken into account if reactions with substrates containing such strongly nucleophilic functional groups are to be performed. 

The nucleophiles that are used for synthetic purposes include water, alcohols, carboxylate ions, hydroperoxides, amines, and nitriles. After the addition step is complete, the mercury is usually reductively removed by sodium borohydride. The net result is the addition of hydrogen and the nucleophile to the alkene. The regioselectivity is excellent and is in the same sense as is observed for proton-initiated additions.16 Scheme 4.1 includes examples of these reactions. Electrophilic attack by mercuric ion can affect cyclization by intramolecular capture of a nucleophilic functional group, as illustrated by entries 9-11. Inclusion of triethylboron in the reduction has been found to improve yields (entry 9).17... 

The trialkyloxonium salts are powerful alkylating agents. Trimethyl- and triethyloxonium tetrafluoroborates, in particular, have been widely employed for methylation and ethylation of sensitive or weakly nucleophilic functional groups. Alkylations of over 50 such functional groups have been reported in the literature. Examples include amides,4,7,13 16 lac-... 

Highly Lewis basic and nucleophilic functional groups are not compatible with zinc carbenoids. The methylation or ylide formation of heteroatoms is one of the most important side reactions of these reagents. For example, amines, thioethers and phosphines readily react with the zinc reagents to generate ammonium salts", sulfonium" and phosphonium ylides" ". Terminal alkynes generally lead to a large number of by-products". ... 

The second chemical principle of interest here is that many biochemical reactions involve interactions between nucleophiles (functional groups rich in electrons and capable of donating them) and electrophiles (electron-deficient functional groups that seek electrons). Nucleophiles combine with, and give up electrons to, electrophiles. Common nucleophiles and electrophiles are listed in Figure 6-21. Note that a carbon atom can act as either a nucleophile or an electrophile, depending on which bonds and functional groups surround it. 

Under these conditions, other nucleophilic functional groups may also be alkylated, which limits the range of compounds accessible by this methodology. Moreover, volatile alkylating agents are often highly toxic and therefore problematic to handle. 

Some unusual nucleophile functional groups that have been utilized in cyclofunctionalizations to form bridged ring systems include cyclic hemiacetals (equation 18)73 and epoxides (equation 19).87 The cyclizations in equation (20) involve a cyclic enol ether as the reactive ir-system and have been used in syn-... 

Taddei has developed a soluble PEG supported scavenger 53 to capture a variety of nucleophilic functional groups (Scheme 13) [21]. This scavenger was based on an electrophilic dichlorotriazine core and relied on selective precipitation (by the addition of ether to acetonitrile) to remove it from the reaction mixture. This scavenger 53 is particularly versatile, and has been used to remove primary, secondary and tertiary alcohols, diols and thiols... 

If the N-substituent contains a nucleophilic functional group, it is an ideal situation for an attack on the lactam carbonyl group. Thus, acid treatment of l-(2-aminophenyl)3-ethyl-3-phenyl-azetidine-2-one (VI/747), Scheme VI/16) gives the diazepine derivative VI/75 [69] in high yield. If this reaction takes place... 

All of these disconnections relied on the reaction of a carbon electrophile with a nucleophilic functional group. The alternative, reaction of a carbon nucleophile (such as a Grignard reagent) with an electrophilic functional group, allows us to do C-C disconnections on alcohols, For example, this compound, which has a fragrance reminiscent of lilac, is a useful perfume for use in soap because (unlike many other perfumes that are aldehydes or ketones) it is stable to alkali. 

So far we have discussed polymerization that has been essentially of one kind—bifunctional molecules have combined in normal ionic reactions familiar from the rest of organic chemistry where a nucleophilic functional group attacks an electrophilic functional group. The new bonds have generally been G-O or C-N. We need now to look at the polymerization of alkenes. In these reactions, n r knnric will bp for ed and many of the reactions may be new to you,... 

The use of a strong Lewis acid (AI2CI6) precludes the use of arenes with nucleophilic functional groups (anilines, benzoate esters, etc.) and may also lead to the rearrangement of alkyl substituents bound to the arene. 

This is a protein labeling reagent which readily reacts with amines and other nucleophilic functional groups. This reagent has been used, for example, to study the glucagon receptor in hepatocyte plasma membranes lodosulfanilic acid... 

Competition experiments between two ir-bonded nucleophiles within the same molecule were studied in an attempt to identify reaction parameters and factors responsible for regioselectivity. These experiments, summarized in heme 12, demonstrated that the dithioacetal (initiating carbocation) is in competition with two nucleophilic functional groups within the same molecule, a silyl enol ether and a vinylsilane. In this instance, when the thioacetal (29) was treated with DMTSF, complete chemoselectiv-... 

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