Kinetics of the Siloxyvinylcyclopropane Rearrangement Using a Micro Stirred Flow Reactor

Article abstract of DOI:10.1021/jo00316a006

The kinetics of the thermal rearrangement of 1-(1-(trimethylsiloxy)cyclopropyl)cyclopentene (3), 5-methyl-1-(1-(trimethylsiloxy)cyclopropyl)cyclopentene (5), 1-cyclopropyl-1-(trimethylsiloxy)ethylene (7), and 1-((Z)-2-methyl-1-(trimethylsiloxy)cyclopropyl)cyclopentene (9) was investigated on a micro stirred flow apparatus.Siloxyvinylcyclopropanes 3, 5, and 7 rearrange cleanly to their respective cyclopentyl enol silyl ethers with a calculated ΔG^% (350 deg C) of 43.8 kcal/mol for 3, 42.9 kcal/mol for 5, and 51.3 kcal/mol for 7.Siloxyvinylcyclopropane 9 rearranged to4-cyclopentylidene-4-(trimethylsiloxy)but-1-ene (10) via the homo 1,5 hydrogen shift with a calculated ΔG^% (350 deg C) of 39.2 kcal/mol.A comparison of the ΔG^%-s for the rearrangement of siloxyvinylcyclopropanes is made with those of other substituted vinylcyclopropanes.