 If the ylide carbon is substituted with an alkyl group the reagent is referred to as an unstabilized ylide . The size of the alkyl groups are the major factors in selectivity with these reagents . 
 If the ylide carbon is substituted with an alkyl group the reagent is referred to as an unstabilized ylide . The size of the alkyl groups <a href='drop_aux' title='1'><mark>are</mark></a>the major factors in selectivity with these reagents . 
If da ylide carbon is substituted wit an alkyl group the reagent is referred to as an unstabilized ylide . The size of the alkyl groups the major factors in selectivity wwitthese reagents .