Migration alkoxy groups

These data demonstrate that a photorearrangement reaction of 1-alkoxy group actually occurs. We continue to speculate that any substituents at the 1 position of indoles may migrate to 3, 4, and/or 6 positions upon photoirradiation. 

An interesting and mechanistically unsettled problem of organocobalt chemistry is the 1,2-shift of a /1-carboxy or -hydroxy group in the homolytic Co—C bond fission-recombination process. The evidence for cobalt participation in the rearrangement is substantial, but its role is not yet clarified (Scheme 103). The heterolytic process also appears to be viable in the migration of a /1-hydroxy or -alkoxy group. 

Migration of tertiary alkyl groups in the dichloromethyl methyl ether reaction does however mean that ketones cannot be synthesized using thexylborane and the approach adopted in the carbonylation and cyanidation processes. In order to obtain ketones by this route, boranes bearing chloro or alkoxy groups, i.e. groups of very low migratory aptitude, have to be used as substrates (Equation B3.17). 

The chemistry of acylcarbenes has been discussed extensively in Houben-Weyl, Vol. E19b, p 1022ff. There are several classes of acylcarbenes that are not suited for intra- or intermolecular cyclopropanation reactions due to the existence of more favored reaction pathways. For example, no cyclopropanation reactions of trialkoxymethyl- or dialkoxymethylcarbenes are known, since these carbenes undergo fast 1,2-migration of an alkoxy group to form alkoxyal-kenes. For various other reasons, cyclopropanation reactions involving (l-iminoalkyl)carbenes, thioxo-, and selenoxocarbenes are unknown. 

Acylphosphonic acids (1-oxoalkylphosphonic acids) and their dialkyl esters undergo acid-catalyzed fission with the formation of carboxylic acids (or their alkyl esters) using a suiphonic acid as the catalyst the formation of an alkyl carboxylace is accompanied by that of an alkyl sulphonate. The reaction may be visualized as occurring through protonation on the carbonyl oxygen and migration of an alkoxy group from phosphorus... 

The fundamental reaction in the hydrolysis of metal alkoxides is a nucleophilic substitution (Sn ) that involves a nucleophilic addition of OH group onto the electrophilic metal center (M ). As a result, the coordination number (CN) of the metal atom is increased in the transition state, which leads to the migration of proton toward an alkoxy group, consequently knocking off the protonated ROH ligand (Figure 12). The chemical reactivity of metal alkoxides toward nucleophilic reactions mainly depends on the strength of the nucleophile, the electrophilic character of the metal atom, and its ability to increase the CN. 

Alkoxyoxindoles from alkoxylamines N- C-Alkoxy group migration... 

Silver perchlorate Migration of alkoxy groups with skeletal rearrangement... 

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