Nucleophiles organolithium reagents/cuprates

The chemical behavior of heteroatom-substituted vinylcarbene complexes is similar to that of a,(3-unsaturated carbonyl compounds (Figure 2.17) [206]. It is possible to perform Michael additions [217,230], 1,4-addition of cuprates [151], additions of nucleophilic radicals [231], 1,3-dipolar cycloadditions [232,233], inter-[234-241] or intramolecular [220,242] Diels-Alder reactions, as well as Simmons-Smith- [243], sulfur ylide- [244] or diazomethane-mediated [151] cyclopropanati-ons of the vinylcarbene C-C double bond. The treatment of arylcarbene complexes with organolithium reagents ean lead via conjugate addition to substituted 1,4-cyclohexadien-6-ylidene complexes [245]. 

Development of the chemistry of the salt (156) continues. When converted into the alkoxyphosphonium salts (157) and treated with, e.g., methyl-lithium or lithium dimethylcuprate, alkylation at the alkoxy carbon to form R—Me derivatives only occurs to a small extent, due to competition from the strongly nucleophilic N-methylanilide ion. However, alkylation (and arylation) at the alkoxy carbon has been achieved by the reaction of the salt (156) with mixed cuprates derived from an allylic alcohol, copper(i) iodide, and an organolithium reagent, enabling direct substitution of the hydroxy-group of allyl alcohols by alkyl or phenyl groups in a regio- and stereo-selective manner. ... 

The imine 19 derived from a phenylethylamine has been reported to react with various nucleophiles, such as organolithium reagents and cuprates, to generate the diastereoenriched amine following hydrogenolysis (H2/Pd) of the chiral auxiliary. However, the diastereoselectivities of these reactions are typically modest [36 38]. The seminal works of Takahashi [39] and later Pridgen [40] demonstrated that higher... 

Derivatives of azete are only known as unstable reaction intermediates. Oxetane and azetidine are considerably less reactive than their three-membered connterparts (oxetane reacts with hydroxide anion 10 times more slowly than does oxirane), but nonetheless do undergo similar ring-opening reactions, for example oxetane reacts with organolithium reagents in the presence of boron triflnoride, or with cuprates, and azetidine is opened on heating with concentrated hydrochloric acid. Azetidininm ions react mnch more easily with nucleophiles. ... 

The nucleophilic substitution of a halogenocompound by an organometallic reagent (e.g. an organolithium or -magnesium) proceeds smoothly through the formation of cuprates. This technique has been applied to the synthesis of various natural products (Equation 14) and of biologically active compounds such as antibiotics (Equation 15) (see also [13]). 

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