Organomercury reagents

C02C0R, CONR2) CONRCOR, CN See page 1809, Section 6. 

NaOMe / CuCl2 CuCl(OMe) CuC12-4H20, r-BuNH2 

Roberts, A. A. Khalaf, Friedel-Crafts Alkylation Chemistry, Marcel Dekker, New York (1984) 

For a review of radical cyclizadons, see Org Rxs 48 301 (1996). See also page 1329, Section 6. 

NaOMe/CuCl2 CuCl(OMe) CuCl2-4H20, f-BuNH2 

Me02CNHCH(C02Me)SC0Et + HjC CHR MeO2CNHCH(C02Me)CH2CH2R 

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Cacchi and Palmier (83T3373) investigated a new entry into the quinoline skeleton by palladium-catalyzed Michael-type reactions. They found that phenyl mercurial 134 was a useful intermediate for the synthesis of quinoline derivatives, and that by selecting the reaction conditions the oxidation level of the heterocyclic ring in the quinoline skeleton can be varied. On such example is shown in Scheme 16. PdCla-catalyzed coupling between organomercurial reagent 134 and enone 135 delivered adduct 136 which was subsequently cyclized to quinoline 137 under acidic conditions. 

Organomercury reagents do not react with ketones or aldehydes but Lewis acids cause reaction with acyl chlorides.187 With alkenyl mercury compounds, the reaction probably proceeds by electrophilic attack on the double bond with the regiochemistry being directed by the stabilization of the (3-carbocation by the mercury.188... 

Entry 5 is an example of the use of fra-(trimethylsilyl)silane as the chain carrier. Entries 6 to 11 show additions of radicals from organomercury reagents to substituted alkenes. In general, the stereochemistry of these reactions is determined by reactant conformation and steric approach control. In Entry 9, for example, addition is from the exo face of the norbornyl ring. Entry 12 is an example of addition of an acyl radical from a selenide. These reactions are subject to competition from decarbonylation, but the relatively slow decarbonylation of aroyl radicals (see Part A, Table 11.3) favors addition in this case. 

Examples involving the use of organomercury reagents as nucleophiles in aqueous media are also known. Bergstrom studied the synthesis of C-5-substituted pyrimidine nucleosides in aqueous media via a mercurated intermediate using Li2PdCl4 as a catalyst (Eq. 6.42).136... 

Some of the earlier efforts utilizing organometallics for displacement of halogen from phosphorus for C-P bond generation involved organomercury reagents. Of course, such reagents pose a serious toxico-... 

Similar to the tin- and zinc-based methodologies, electron deficient alkenes were found to strongly catalyze the reductive elimination step.155 156-395 Organomercury reagents are also believed to add via metal addition.385... 

P. Knochel, Organozinc, Organocadmium and Organomercury Reagents, in Comprehensive Organic Synthesis (B. M. Trost, I. Fleming, Eds.), Vol. 1, 211, Pergamon Press, Oxford, 1991. 

Additional synthetic protocols are available for the preparation of research quantities of aluminum alkyls that are not commercially available by the above routes. Of these, reaction of an organomercury reagent with aliuninum metal... 

Tor a review of the use of phenyl(trihalomethyl)mercury compounds as dihalocarbene or dihalocarbenoid precursors, see Seyferth, D. Acc. Chem. Res. 1972, 5, 65. For a review of the synthesis of cyclopropanes with the use of organomercury reagents, see Larock, R.C. Organomercurcury Compounds in Organic Synthesis, Springer, NY, 1985, pp. 341-380. 

These routes are often more desirable than those involving organomercury reagents due to toxicity concerns. 

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