The previously unknown 2-(trialkylsilyloxy)allylidenecyclopropanes 2a-d have been prepared by silyl-enolization of the easily available cyclopropylidenealkanones 1-R1 in good yields. Dienes 2a-d readily react with a variety of dienophiles at temperatures ranging from 0 to 130°C to give derivatives 5-10 of 5-(trialkylsilyloxy)spiro-[2.5]oct-4-ene or the corresponding hydrolysis products 10, 12. Weak dienophiles like cyclohexenone and cyclopentenone give spiro[2.5]octan-5-one derivatives only under BF3 catalysis and with poor yields.
- BF catalysis
- Diels-Alder reactions
- Ring strain and donor activated dienes
- spirocyclopropane mimic of gem-dimethyl groups
ASJC Scopus subject areas
- Drug Discovery
- Organic Chemistry