Borylation and rearrangement of alkynyloxiranes: a stereospecific route to substituted α-enynes

authors

• Fuentespina Ruben Pomar
• Garcia de La Cruz José Angel
• Durin Gabriel
• Mamane Victor
• Weibel Jean-Marc
• Pale Patrick

keywords

• Boron
• Enyne
• Lithium
• Oxirane
• Rearrangement

document type

abstract

1,3-Enynes are important building blocks in organic synthesis and also constitute the key motif in various bioactive natural products and functional materials. However, synthetic approaches to stereodefined substituted 1,3-enynes remain a challenge, as they are limited to Wittig and cross-coupling reactions. Herein, stereodefined 1,3-enynes, including tetrasubstituted ones, were straightforwardly synthesized from cis or trans-alkynylated oxiranes in good to excellent yields by a one-pot cascade process. The procedure relies on oxirane deprotonation, borylation and a stereospecific rearrangement of the so-formed alkynyloxiranyl borates. This stereospecific process overall transfers the cis or trans-stereochemistry of the starting alkynyloxiranes to the resulting 1,3-enynes. 1416

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