Chiral C(4)-substituted (E)- or (Z)-1-alkynyl-1-trimethylsilyloxy-2-butene systems provide anti-(Z) or syn-(Z) conjugated dienyne, with a very high level of stereocontrol, on treatment with BF3·OEt2 in CH2Cl2 at -50°C in the presence of allyltrimethylsilane. The Cieplak conformation for (Z)-substrates and neighboring-group participation for (2)-substrates are considered to be responsible for the stereochemical consequences.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry