text:  The selectivity of some <unk> may be drastically improved in some cases with the addition of coordinating groups alpha to the <unk> ring as <unk> <unk> and <unk> in the table above . In these instances it is proposed that the reaction proceeds through a closed transition state where the metal <unk> is stabilized by <unk> from the sulfate and coordinating groups on the camphor skeleton . 
  