Diels–Alder study casts doubt on innate endo-selectivity
New evidence questions the Alder endo rule of simple Diels–Alder reactions
Researchers have experimentally proved that the simplest Diels–Alder reaction between 1,3-butadiene and mono-substituted alkenic dienophiles is not endo-selective as previously thought. Mick Sherburn, who led the work at the Australian National University, says many chemists will be surprised by their findings, and hopes they change the way that people think about the reaction and teach it.