Carbon nucleophiles alkenyl ethers

Carbon-centered nucleophiles can also be used to advantage in the reaction with epoxides. For example, the lithium enolate of cyclohexanone 96 engages in nucleophilic attack of cyclohexene oxide 90 in the presence of boron trifluoride etherate to give the ketol 97 in 76% yield with predominant syn stereochemistry about the newly formed carbon-carbon bond <03JOC3049>. In addition, a novel trimethylaluminum / trialkylsilyl triflate system has been reported for the one-pot alkylation and silylation of epoxides, as exemplified by the conversion of alkenyl epoxide 98 to the homologous silyl ether 99. The methyl group is delivered via backside attack on the less substituted terminus of the epoxide <03OL3265>. 

Similarly, at a carbon anode in 1 1 MeOH-THF, anodic cyclization of allylsilane enol ether (XCIX) proceeded stereoselectively to give (C) [Eq. (63)]. The use of allyl silanes as the unsaturated nucleophilic component in such radical-cation cyclizations proved to be beneficial, though the exact mechanistic details remain somewhat speculative [147]. The method represents an improvement over earlier methods involving anodic cyclization of alkenyl-substituted enol acetates [148]. 

The Claisen rearrangement of aliphatic allyl vinyl ethers, when promoted by trialkylaluminium compounds, provides a route to -alkenyl alcohols (Scheme 26) by uptake of a nucleophile on the aldehydic carbon produced. 6,e-Alkynyl alcohols are available from sterically guided 1,4-addition of lithium acetylides to propenyl trityl ketone followed by reductive cleavage of the trityl group. ... 

Alkyl and 2-Alkenyl Halides or Sulfonates Ring Opening of Cyclic Amines and Ethers Addition onto Carbon-Carbon Multiple Bonds Addition onto Heteroconjugated Multiple Bonds Nucleophilic Substitution of 1-Alkenyl Halides Nucleophilic Addition onto Arenes and Hetarenes Substitution of Halo-, Alkoxy-, and Metalloarenes or -hetarenes Addition onto Nonaromatic Carbon-Nitrogen Multiple Bonds Addition onto Carbonyl Compounds... 

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