Can Wolff Kishner and Clemmensen Method be used to reduce alkyne or alkene. If so do they produce syn addition or anti addition product. ?
Zinc plus a proton source is known to reduce propiolates in THF Tet. Letts. 46 5613
Rieke Zinc has been reported to reduce alkynes to *cis-*alkenes Tet. Letts. 32 299 If you add catalytic Ni then Zn will reduce alkynes selectively to cis alkenes or trans alkenes depending on conditions 3 though this probably operates through Ni(O).
Zn/H+ does not reduce unactivated alkenes. Alkenes conjugated with an EWG may be reduced.
W-K reduction relies on the hydrazine adding to a ketone to form a hydrazone in the 1st step. Nothing comparable can occur with an alkene. However hydrazine can reduce alkenes under different conditions by Di-imide reduction review article.