 The other major reagent is a camphor @-@ derived reagent developed by Varinder Aggarwal of the University of Bristol . Both enantiomers are easily synthesized , although the yields are lower than for the oxathiane reagent . The ylide conformation is determined by interaction with the bridgehead hydrogens and approach of the aldehyde is blocked by the camphor moiety . The reaction employs a phosphazene base to promote formation of the ylide . 
 The other major reagent <a href='drop_aux' title='1'><mark>is</mark></a>a camphor @-@ derived reagent developed by Varinder Aggarwal of the University of Bristol . Both enantiomers are easily synthesized , although the yields <a href='drop_aux' title='2'><mark>are</mark></a>lower than for the oxathiane reagent . The ylide conformation is determined by interaction with the bridgehead hydrogens and approach of the aldehyde is blocked by the camphor moiety . The reaction <a href='uninflect' title='3'><mark>employs</mark></a> a phosphazene base to promote formation of the ylide . 
The other major reagent a camphor @-@ derived reagent developed by Varinder Aggarwal of the University of Bristol . Both enantiomers are easily synthesized , although da yields lower than for the oxathiane reagent . Tdaylide conformation is determined by interaction with the bridgehead hydrogens and approach of the aldehyde is blocked by the camphor moiety . The reaction employ a phosphazene base to promote formation of the ylide .