Process for the functionalization of heteroalkanes and arenes
Provided are methods and materials for the functionalization of a heteroalkane or arene using an oxidizing electrophile as a stoichiometric agent or catalyst. The reaction involves the replacement of a hydrogen atom on an sp3-hybridized carbon atom of the heteroalkane or of a hydrogen atom on an sp2-hybridized carbon atom of the arene. A main group element organometallic intermediate is formed that undergoes further conversion to a functionalized heteroalkane or arene.
1. A process of preparing a functionalized compound, comprising:
(a) providing a compound that is a heteroalkane or an arene,
wherein
the heteroalkane comprises at least one sp 3 -hybridized carbon atom bearing a hydrogen atom and at least one heteroatom other than a carbon or hydrogen atom, and
the arene comprises at least one sp 2 -hybridized carbon atom bearing a hydrogen, and optionally comprising
(i) one or more substituents comprising at least one sp 3 -hybridized carbon atom,
(ii) one or more heteroatoms to form a heteroarene and/or at least one substituent comprising a heteroatom, or
(iii) both (i) and (ii),
(b) contacting the compound with
(i) an oxidizing electrophile comprising a main group element in oxidized form, wherein the main group element is selected from the group consisting of gallium, germanium, arsenic, selenium, bromine, indium, tin, antimony, tellurium, iodine, thallium, lead, and bismuth, or
(ii) an oxidant and a reduced form of the oxidizing electrophile, to provide an initial reaction product, and
(c) contacting the initial reaction product with a functionalized reactant selected from the group consisting of an oxygen acid, a nitrogen-containing functionalized reactant, a stannylation functionalized reactant, a sulfur-containing functionalized reactant, a formylation functionalized reactant, a phosphine functionalized reactant, a base, a carbonylation functionalized reactant, and a halogenation functionalized reactant, wherein a functionalized portion of the functionalized reactant replaces the main group element on the initial reaction product to provide the functionalized compound.
2. The process of claim 1 , wherein step (b) comprises contacting the compound with an oxidizing electrophile comprising a main group element in oxidized form.
3. The process of claim 1 , wherein step (b) comprises contacting the compound with an oxidant and a reduced form of the oxidizing electrophile.
4. The process of claim 1 , wherein the oxidizing electrophile comprises thallium, lead, bismuth, antimony, selenium, tellurium, or a mixture thereof, each of which is in oxidized form.
5. The process of claim 4 , wherein the oxidizing electrophile comprises thallium(III), lead(IV), bismuth(V), or Sb(V), or any mixture thereof.
6. The process of claim 1 , wherein the oxidizing electrophile comprises iodine in oxidized form.
7. The process of claim 1 , wherein the oxidizing electrophile is a salt that includes a counterion of the main group element in oxidized form, and wherein the counterion is a conjugate anion of an acid.
8. The process of claim 1 , wherein the oxidizing electrophile is of formula M +n X n , wherein M is a metal or non-metal main group element cation in an oxidation state of n, X is an anionic counterion, and n is the number of anionic charges necessary to balance the n+ positive charge of the metal ion.
9. The process of claim 1 , wherein the oxidizing electrophile comprises one or more trifluoroacetate, acetate, sulfate, or alkylsulfonate anions.
10. The process of claim 1 , wherein the contacting of step (b) takes place in an acidic medium.
11. The process of claim 10 , wherein the acidic medium comprises a mineral acid, a carboxylic acid, a sulfonic acid, or any combination thereof.
12. The process of claim 1 , further comprising separating the functionalized compound and an electrophile reduction product that is formed by the oxidizing electrophile.
13. The process of claim 12 , further comprising contacting the separated electrophile reduction product and an oxidizing regeneration reagent to regenerate the oxidizing electrophile, wherein the oxidizing regeneration reagent preferably comprises hydrogen peroxide, oxygen, ozone, nitric acid, or a halogen.
14. The process of claim 13 , wherein the electrophile reduction product and the oxidizing regeneration reagent are contacted in the presence of an oxidative regeneration catalyst, wherein the oxidative regeneration catalyst preferably comprises copper, silver, iron, or vanadium.
15. The process of claim 1 , wherein the oxidizing electrophile comprising a main group element in oxidized form is present in less than stoichiometric quantities relative to the heteroalkane or arene and acts as a catalyst.
16. The process of claim 1 , wherein a stoichiometric amount of the oxidizing electrophile reacts with the compound to form the initial reaction product.
17. The process of claim 1 , wherein step (c) further comprises contacting the initial reaction product and functionalized reactant with water, an oxidant, or both.
18. The process of claim 1 , wherein the functionalized reactant is selected from the group consisting of an oxygen acid, a hydrazine, a hydroxylamine, ammonia, a primary amine, a secondary amine, a stannous salt, octasulfur, alkylthiol, a phosphine, a weak base, formaldehyde, carbon monoxide, and a halide.
19. The process of claim 1 , wherein the compound is a heteroalkane that is an alkyl monoester.
20. The process of claim 1 , wherein the compound is an arene that comprises an aryl ring system or a heteroaryl ring system.
21. The process of claim 1 , wherein the oxygen acid is trifluoroacetic acid, acetic acid, methanesulfonic acid, aqueous solutions thereof, or a combination thereof.
22. The process of claim 1 , wherein the nitrogen-containing functionalized reactant is hydrazine, hydroxylamine, ammonia, a primary amine, or a secondary amine.
23. The process of claim 1 , wherein the stannylation functionalized reactant is a stannous salt.
24. The process of claim 1 , wherein the sulfur-containing functionalized reactant is octasulfur or an alkylthiol.
25. The process of claim 1 , wherein the formylation functionalized reactant is formaldehyde.
26. The process of claim 1 , wherein the phosphine functionalized reactant is a monosubstituted phosphine, disubstituted phosphine, or trisubstituted phosphine.
27. The process of claim 1 , wherein the base is a conjugate base of acetate or trifluoroacetate.
28. The process of claim 1 , wherein the carbonylation functionalized reactant is carbon monoxide.
29. The process of claim 1 , wherein the halogenation functionalized reactant is a halide.