Lead-carbon bonds group

Reactions at a Group VIII Metal Center The Ni, Pd, Pt Triad 10.3.8.9. Reactions of Tin-Carbon and Lead-Carbon Bonds... 

Organic derivatives of lead are less stable to heat and light and more readily decomposed than those of other elements of the fourth main Group also the lead-carbon bond is considerably more easily broken by acids and oxidizing agents. 

Some special procedures which are not discussed are mentioned in Table III. Also of interest are those reactions of functionally substituted organolead compounds, in which the functional groups are exchanged without cleavage of the lead-carbon bond (see Table III). 

The transition state involves the carbonyl oxygen of one carboxyl group—the one that stays behind—acting as a proton acceptor toward the hydroxyl group of the carboxyl that IS lost Carbon-carbon bond cleavage leads to the enol form of acetic acid along with a molecule of carbon dioxide... 

Chiral oxazolines developed by Albert I. Meyers and coworkers have been employed as activating groups and/or chiral auxiliaries in nucleophilic addition and substitution reactions that lead to the asymmetric construction of carbon-carbon bonds. For example, metalation of chiral oxazoline 1 followed by alkylation and hydrolysis affords enantioenriched carboxylic acid 2. Enantioenriched dihydronaphthalenes are produced via addition of alkyllithium reagents to 1-naphthyloxazoline 3 followed by alkylation of the resulting anion with an alkyl halide to give 4, which is subjected to reductive cleavage of the oxazoline moiety to yield aldehyde 5. Chiral oxazolines have also found numerous applications as ligands in asymmetric catalysis these applications have been recently reviewed, and are not discussed in this chapter. ... 

Addition of trimethylaluminum to norcamphor (3), regardless of the stoichiometry of the reactants, leads to a mixture of the diastereomeric alcohols in a ratio of 95 5 also in favor of the erafo-alcohol6. Examination of the norcamphor model indicates that endo attack is sterical-ly more hindered than exo attack. However, steric interaction may not fully account for the exceptionally high exo selectivity. On the other hand, no severe torsional strain is involved if the nucleophile approaches the carbonyl group from the exo side, however, a nucleophile approaching from the endo side encounters torsional strain between the incipient bond and the C-l to C-6 carbon-carbon bond. Thus, in the case of norcamphor, steric and stereoelectronic factors reinforce each other, resulting in a strong directional influence for exo attack. 

Julia and Paris120 described an olefin synthesis, based on the use of a sulphonyl group which directs the formation of a carbon-carbon bond. Subsequent reductive elimination with sodium amalgam leads to the alkene, as outlined in equation (50). The reaction sequence is similar in principle to an olefin synthesis first developed by Cornforth121. The yields of all steps are generally above 80%. 

---