 The most successful reagents employed in a stoichiometric fashion are shown below . The first is a bicyclic oxathiane that has been employed in the synthesis of the β @-@ adrenergic compound dichloroisoproterenol ( DCI ) but is limited by the availability of only one enantiomer of the reagent . The synthesis of the axial diastereomer is rationalized via the 1 @,@ 3 @-@ anomeric effect which reduces the nucleophilicity of the equatorial lone pair . The conformation of the ylide is limited by transannular strain and approach of the aldehyde is limited to one face of the ylide by steric interactions with the methyl substituents . 
 The most successful reagents employed in a stoichiometric fashion are shown below . The first <a href='drop_aux' title='1'><mark>is</mark></a>a bicyclic oxathiane <a href='null_relcl' title='2'><mark>that</mark></a><a href='been_done' title='3'><mark>has</mark></a> been employed in the synthesis of the β @-@ adrenergic compound dichloroisoproterenol ( DCI ) but is limited by the availability of only one enantiomer of the reagent . The synthesis of the axial diastereomer is rationalized via the 1 @,@ 3 @-@ anomeric effect which <a href='uninflect' title='4'><mark>reduces</mark></a> the nucleophilicity of the equatorial lone pair . The conformation of the ylide is limited by transannular strain and approach of the aldehyde is limited to one face of the ylide by steric interactions with the methyl substituents . 
The most successful reagents employed in a stoichiometric fashion are shown below . The first a bicyclic oxathiane done been employed in the synthesis of the β @-@ adrenergic compound dichloroisoproterenol ( DCI ) but is limited by da availability of only one enantiomer of tdareagent . Thdaynthesis of the axial diastereomer is rationalized via the 1 @,@ 3 @-@ anomeric effect which reduce the nucleophilicity of thedauatorial lone pair . The daformation of the ylide is limited by transannular strain and approach of the adahyde is limited to one face of the ylda by steric interactions with the metda substituents .