▁denotes ▁hal ogen ) ▁with ▁an ▁organ ol ith ium ▁( RL i ) ▁or ▁Gr ign ard ▁re agent ▁( R M g X ). ▁The ▁first ▁reported ▁pl um by l ene , ▁[ (( CH 3 ) 3 Si ) 2 CH ] 2 P b , ▁was ▁synth es ized ▁by ▁Michael ▁F . ▁L app ert ▁et ▁al ▁by ▁trans met all ation ▁of ▁P b Cl 2 ▁with ▁[ (( CH 3 ) 3 Si ) 2 CH ] Li . ▁The ▁addition ▁of ▁equ im olar ▁R Li ▁to ▁P b X 2 ▁produces ▁the ▁mon oh al ogen ated ▁pl um by l ene ▁( R P b X ); ▁addition ▁of ▁ 2 ▁equival ents ▁leads ▁to ▁dis ub st it uted ▁pl um by l ene ▁( R 2 P b ). ▁Adding ▁an ▁organ ol ith ium ▁or ▁Gr ign ard ▁re agent ▁with ▁a ▁different ▁organ ic ▁subst itu ent ▁( i . e . ▁R ’ Li / R ’ M g X ) ▁from ▁R P b X ▁leads ▁to ▁the ▁synth esis ▁of ▁heter ole ptic ▁pl um by len es ▁( R R ’ P b ). ▁D ial k yl -, ▁di ary l -, ▁diam ido -, ▁d ith iop l um by len es , ▁and ▁mon oh al ogen ated ▁pl um by elen es ▁have ▁been ▁successfully ▁synth es ized ▁this ▁way . ▁▁▁▁ ▁Trans met all ation ▁with ▁[ (( CH