Tertiary carbon atom tert

As illustrated in Fig. 20.1, the C-C bond that is broken in the hydrogenolysis of alkyl cyclopropanes is that one between the two least substituted carbon atoms of the ring. With unsymmetrical 1,2-dialkyl-cyclopropanes (1, R iR ) the bond adjacent to the smaller alkyl group is preferentially cleaved. When coupled with the facile cyclopropanation of alkenes, the hydrogenolysis of alkyl cyclopropanes over platinum oxide has served as a useful means of introducing a methyl group onto a tertiary carbon atom as illustrated by the preparation of tert-butyladamantane (3) (Eqn. 20.1) and the 9-methyldecalins, 5 and 6 (Eqn. 20.2). > ... 

The obvious dilferences in the reactivity of primary, secondary, and tertiary carbon atoms are normally quite satisfactory to explain their selectivity. Esterification of alcohols invariably adopts the same sequence i.e., pri->sec->tert. In fact, the tertiary alcohols are generally quite rmreactive with regard to the esterification. 

One further word about naming alkyl groups the prefixes sec- (for secondary) and tert- (for tertiary) used for the C4 alkyl groups in Figure 3.3 refer to the number of other carbon atoms attached to the branching carbon atom. There are four possibilities primary (1°), secondary (2°), tertiary (3°), and quaternary (4°). 

All tertiary alkyl groups (a-d) are branched in the same way on the a-carbon atom and differ in the length of the carbon chain and the nature of further branching the activity first decreases until substitution by the alkyl group with three carbon atoms in the main chain (i.e., tert-amyl), then it increases to the ferf-dodecyl group (C6 chain) nevertheless, the... 

The prefixes sec and tert are really short for secondary and tertiary, terms that refer to the carbon atom that attaches these groups to the rest of the molecular structure. 

The marked dependence of 7( P—M— P) on stereochemistry for complexes of the platinum group metals has been used in NMR spectroscopy for several years 109,115). For methyl or tert-h xty tertiary phosphines, when the two phosphines are mutually trans then a triplet pattern results, but if the two phosphines are mutually cis, then a doublet pattern results as a consequence of the spectrum being of the AA X X type and the dependence of V( P—M— P) on stereochemistry. Exactly the same behavior is found in NMR spectroscopy with the advantage that the technique is far more versatile and is not normally troubled by resolution problems. Thus for cr-[RhCl3(CO)(PBu"2Ph)2] triplet patterns have been observed for six of the eight different carbon atoms in the tertiary phosphine ligand 164). When —M—is... 

Tor the butyl groups, sec- indicates attachment to the chain through a secondary carbon, a carbon atom attached to tu-i) other carbon atoms. The designation tert- signifies attachment through a tertiary carbon, a carbon attached to three other carbon atoms. 

In the mixture of secondary alcohol or primary alcohol with tertiary esters, the products of secondary alcohol esters or primary alcohol esters would be further chemically combined immediately. A hydrogen atom in the raw esters would react with a-carbon atom to form alcohols, which would not be oxidized. Transesterification reaction would happen for tert-butyl nitrite because of the instability of NO. 

Initiation gives the tert-butyl cation (eq. 14.14), which, in the propagation step, adds to the CH2 carbon of the double bond in a Markovnikov manner to produce another tertiary carbocation and so on (eq. 14.15). The chain is terminated by loss of a proton from a carbon atom adjacent to the positive carbon (eq. 14.16). 

Alcohols are compounds that contain -OH groups connected to an alkyl carbon. Phenols are similar, but have an -OH group connected directly to an aromatic ring. The terms primary, secondary, and tertiary are used to describe aicohois. in a primary alcohol, a carbon can be connected to one or no other carbon atoms example CH3-OH, methyl alcohol. A secondary is connected to two carbons example isopropyl alcohol. Tertiary describes connections to three other carbons example tert-butyl alcohol (Figure 19-7). 

To see what the prefixes sec- and tert- mean, we must introduce new and important terminology (Fig. 2.34). A primary carbon is a carbon that is attached to only one other carbon atom. A secondary carbon is a carbon attached to two other carbons, and a tertiary carbon is a carbon attached to three other carbons. A quaternary not quarternary) carbon (not shown in Figure 2.34, but we ll see one in a moment) is a carbon that is attached to four other carbons. Thus, the names rcc-butyl and tert-butyl tell you something about the structure. 

Both alkyl bromides have six carbon atoms with a bromine attached to a tertiary carbon, but two different compounds cannot be named tert-hexyl bromide. 

Many types of peroxides (R-O-O-R ) are also utilized, including diacyl peroxides, peroxydicarbonates, peroxyesters, dialkyl peroxides, and inorganic peroxides such as persulfate, the latter being used mainly in water-based systems. The rate of peroxide decomposition as well as the subsequent reaction pathway is greatly affected by the nature of the peroxide chemical structure, as illustrated for fert-butyl peroxyesters in Scheme 4.2. Pathway (a), the formation of an acyloxy and an alkoxy radical via single bond scission, is favored for structures in which the carbon atom in the a-position to the carbonyl group is primary (for example, terf-butyl peroxyace-tate, R = CHg). Pathway (b), concerted two-bond scission, occurs for secondary and tertiary peroxyesters (for example, terf-butyl peroxypivalate, R = C(CH3)3) [1, 2]. The tert-butoxy radical formed in both pathways may decompose to acetone and a methyl radical, or abstract a hydrogen atom to form tert-butanol. 

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