Alkene and Alkyne reactions

Alkene + HBr, ROOR

Br adds on least substituted carbon of the double bond

Alkene + HX

X adds on most substituted carbon of the double bond. 1) Double bond attacks hydrogen from H-X and carbocation forms on most substituted carbon of the double bond. 3) Rearrangement happens if necessary. 4) X- attacks the carbocation

Alkene + H3O+ (acid and water)

OH adds on most substituted carbon of the double bond. 1) Double bond attacks hydrogen from H3O+. 2)Rearrangement occurs if necessary. 3)Water attaches to carbocation. 4)Water deprotonates H from OH2+ ion.

Alkene + 1) Hg(OAc)2, H2O (or other nucleophile) 2)NaBH4

OH adds to most substituted carbon of the double bond WITHOUT SUBSTITUTION. 1)Double bond attacks Hg(OAc)2 and HgOAc- adds to least substituted carbon of the double bond. 2)Hg attacks the carbocation and forms a triangle. 3) H2O attacks backside of former carbocation and triangle is broken. 4) Another H2O attacks H on the OH2+ 5) NaBH4 cleaves HgOAc and replaces with H

Alkene + 1) BH3*THF 2) H2O2, NaOH

OH adds to least substituted carbon of the double bond; H and OH add to same side of the double bond (SYN). 1) Least substituted carbon attacks B of BH3 while an H of BH3 adds to the most substituted carbon. H2O2 and NaOH cleave the BH2 and replace it with an OH.

Alkene + H2, Pd (or Pt or Ni)

SYN addition of H to both carbons of the double bond

Alkene + RCO3H (mCPBA or other peroxy acid)

ANTI addition of OH to both carbons of the double bond.

Alkene + OsO4, NMO (or ROOH)

SYN addition of OH to both carbons of the double bond.

Alkene + KMnO4, cold

SYN addition of OH to both carbons of the double bond.

Alkene + KMnO4, H3O+

Double bonds turn into C=O bonds and H turns into OH; if there are two Hs on a double bonded carbon, they turn into CO2.

Alkene + 1)O3 2)DMS (or Zn in H2O)

Turns C=C bonds into C=O bonds. Leaves Hs alone

Alkene + 1)O3 2)H2O2, ROH

Turns C=C bonds into C=O bonds and turns Hs into OH

Alkene + HIO4

Splits bond between two carbons that both have an OH group attached and turns that bond into C=O for both carbons.

Alkene + carbene (neutral C with lone pair and two bonds)

Forms triangle of Cs across double bond of alkene with the two original bonds still attached to the carbene

Alkyne + LDA (or NaOCH3 or NaNH2)

Deprotonates a terminal alkyne

Alkyne + 1)LDA 2)RX

Adds the R to one (terminal) carbon of the triple bond

Alkane (with two Br and two H on consecutive Cs) + CH3Li (or NaNH2 or NaH STRONG BASES)

Forms a triple bond across the two Cs

Alkyne + H2, Pd/Pt/Ni

Alkane

Alkyne + H2, Lindlar's catalyst

Forms CIS alkene

Alkyne + Na, NH3(l)

Forms TRANS alkene

Alkyne (terminal) + HX + HX + excess small base

shifts triple bond over one over to more inside position on carbon chain

Alkyne + HBr, ROOR

Mixture of cis and trans alkenes with Br on least substituted C

Alkyne + H2SO4, H2O, HgSO4

Creates tautomers - enols (OH group off an alkene carbon) and ketone (C=O). 1) Triple bond attacks H of H3O+ and H adds to the terminal carbon of the alkyne. 2)H2O adds to the vinylic carbocation of the alkene. 3)Another H2O deprotonates the OH2+. 4) The double bond of the enol attacks another H3O+ and an H adds to the least substituted carbon of the alkene. 5) The O of the OH group makes a double bond with the C and gains a positive charge. 6) An H2O deprotonates the HO+=C and creates the ketone product.

*Note: Mercury is a catalyst for this otherwise slow reaction

Alkyne + 1)BH3*THF (or Disiamylborane or 9-BBN) 2)H2O2, NaOH

Creates enol(s) with OH group off the least substituted carbon of the alkene bond, or creates a C=O product. Disiamylborane and 9-BBN are used because a second BH3 might react with the enol (alkene) intermediate. NaOH and H2O react with enol to make the C=O product.

Alkyne + X2 and CCl4

Creates a mixture of ANTI addition of X to each of the carbons of the triple bond or SYN addition of the X to each of the carbons. Excess X2 will lead to an alkane with 2 Xs on each carbon of the former triple bond.

Alkyne + 1)O3 2)H2O

Internal alkyne bonds are cleaved and made into two carboxylic acid bonds on the two halves while terminal alkynes form a carboxylic acid on the most substituted alkyne carbon and a CO2 for the terminal carbon of the alkyne bond