Diastereoselective Diels-Alder Cycloadditions with Chiral 1-(Alkylsulfinyl)-2-nitroalkenes

Article abstract of DOI:10.1021/jo00087a043

Several chiral 2-nitro-1-sulfinylalkenes were prepared and examined for their utility as dienophiles for asymmetric <4 + 2> cycloaddition.Trisubstituted dienophiles 3-6 undergo diastereoselective cycloaddition with cyclopentadiene in the presence of Lewis acids.Even the tetrasubstituted chiral sulfinyl dienophiles 1 and 2 could be coerced into undergoing <4 + 2> cycloaddition to afford the cycloadducts in high yield without concomitant elimination if the reaction was conducted under high pressure.Generally, the Z-sulfinyl dienophiles 1-4 showed higher diastereo- and endo/exo-selectivity than the E-dienophiles 5 and 6.