1- Alkynyl-2,3-epoxy alcohols

Dihydropyranones. Rearrangement of 1 -alkynyl-2,3-epoxy alcohols with HgO and... 

Preparation of highly substituted furans was reported by tandem ring-opening/cyclization reactions of alkynyl epoxy alcohols in moderate to good yields using alcohol as a nucleophile and Cu(OTf)2 as catalyst, as can be seen below <07S3295>. Silver-catalyzed reaction of similar substrates, 3-alkyne-l,2-diols, also furnished the corresponding... 

A stereospecific synthesis of dihydropyran-4-ones 937 can been achieved by a mercury(ll)-catalyzed rearrangement of l-alkynyl-2,3-epoxy alcohols 936. The configuration of the epoxide is transferred unchanged to the product (Equation 367, Table 44) <1998JOC3798>. 

Intramolecular imino ene reaction of an allenylsilane has recently been found to generate cyclohexyl systems with adjacent cis-amino and -alkynyl moieties. This enantioselective ene cyclization was developed for the enantio-selective total syntheses of (—)-montanine (338), (-)-coccinine (351), (-)-pancracine (339), and (-)-brunsvigine (356) (a formal total synthesis) by the same research group (181) (Schemes 40 and 41). A precursor allenylsilane-aldehyde 370 for the enantioselective ene cyclization was synthesized from scalemic epoxy alcohol 369 in nine steps. The allenylsilane-aldehyde 370 thus obtained reacted with A -triphenylphosphinyl-(2-bromo-4,5-methy-lenedioxy)phenylmethylimine in boiling mesitylene to lead to a cyclized product 371 in 63% yield after protodesilylation. Hydrogenation of 371... 

Furans. l-Alkynyl-2,3-epoxy alcohols undergo Hg(II)-catalyzed isomerization. The epoxide ring suffers total destruction during its incorporation into a furan nucleus. 

Sasaki M, Tanino K, Miyashita M (2001) Regioselective alkyl and alkynyl substitution reactions of epoxy alcohols by the use of organoaluminum ate ctunplexes regiochemical reversal of nucleophilic substitution reactions. Oig Lett 3 1765-1767... 

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