Stereochemistry of the reaction of Si-phenyl silenes with butadienes: elaboration of the silacycloadducts to provide a novel route to substituted lactones

Abstract

Silenes generated through a silyl-modified Peterson olefination procedure can be trapped with a range of alkyl butadienes via a [4 + 2] cycloaddition pathway to afford silacycles accompanied by variable amounts of competing ene, [2 + 2] and silene dimer by-products. The silacycles are formed with good chemo- and stereo-selectivity and provide access to diols and lactones via a phenyl-triggered Fleming-Tamao oxidation.