Total synthesis of salinosporamide A and analogs thereof

1. A method of chemical synthesis comprising the steps of:

(a) reacting a compound of formula (I):

with a compound of formula (II):

to form a compound of formula (III):

(b) deprotecting the compound of formula (III) to form a compound of formula (IV):

(c) performing an intramolecular aldol reaction on the compound of formula (IV) to form a compound of formula (V):

(d) cleaving the carbon-carbon double bond of the compound of formula (V) and cyclizing the cleaved double bond with the tertiary hydroxy group to form a compound of formula (VI):

(e) protecting the hemiacetal of the compound of formula (VI) to form a compound of formula (VII):

(f) reducing the COOR 2 group of the compound of formula (VII) to an alcohol to form a compound of formula (VIII):

(g) oxidizing the alcohol of the compound of formula (VIII) to form a compound of formula (IX):

(h) adding R 4 to the compound of formula (IX) by reacting the compound of formula (IX) with an organometallic moiety containing at least one R 4 to form a compound of formula (X):

(i) removing PG 1 on the compound of formula (X) and reductively opening the hemiacetal of the compound of formula (X) to form a compound of formula (XXIII):

(j) protecting the primary hydroxy group of the compound of formula (XXIII) to form a compound of formula (XXIV):

(k) cleaving the aminal group of the compound of formula (XXIV) to form a compound of formula (XXV):

(l) protecting the secondary alcohol of the compound of formula (XXV) to form a compound of formula (XXVp):

(m) converting the primary alcohol group and removing the PG 2 protecting group moiety on the secondary alcohol of the compound of formula (XXVp) to form a compound of formula (XXVI):

(n) removing the PG 3 protecting group moiety on the primary alcohol of the compound of formula (XXVI) to form a compound of formula (XXVII):

(o) protecting the primary alcohol of the compound of formula (XXVII) with the PG 3 protecting group moiety to form a compound of formula (XXVI), wherein the PG 3 can be same or different from the PG 3 in step (m):

(p) performing a lactonization reaction on the compound of formula (XXVI) to form a compound of formula (XXVIII):

(q) removing the PG 3 protecting group moiety on the compound of formula (XXVIII) to form a compound of formula (XV):

wherein:

R 1 is hydrogen or substituted or unsubstituted C 1-6 alkyl;

R 2 is selected from the group consisting of hydrogen, or substituted or unsubstituted variants of the following: C 1-6 alkyl aryl, and arylalkyl;

R 3 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1-6 alkyl, C 3-6 cycloalkyl, C 2-6 alkenyl, C 3-6 cycloalkenyl, aryl, and arylalkyl;

R 4 can be selected from the group consisting of substituted or unsubstituted variants of the following: C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 2 -C 12 alkynyl, C 3 -C 12 cycloalkyl, C 3 -C 12 cycloalkenyl, C 3 -C 12 cycloalkynyl, C 3 -C 12 heterocyclyl, aryl, heteroaryl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, (heterocyclyl)alkyl, acyl, acylalkyl, alkyloxycarbonyloxy, carbonylacyl, aminocarbonyl, azido, azidoalkyl, aminoalkyl, salt of an aminoalkyl, carboxyalkyl, salt of carboxyalkyl, alkylaminoalkyl, salt of an alkylaminoalkyl, dialkylaminoalkyl, salt of a dialkylaminoalkyl, phenyl, alkylthioalkyl, arylthioalkyl, carboxy, cyano, alkanesulfonylalkyl, alkanesulfinylalkyl, alkoxysulfinylalkyl, thiocyanoalkyl, boronic acidalkyl, boronic esteralkyl, guanidinoalkyl, salt of a guanidinoalkyl, sulfoalkyl, salt of a sulfoalkyl, alkoxysulfonylalkyl, sulfooxyalkyl, salt of a sulfooxyalkyl, alkoxysulfonyloxyalkyl, phosphonooxyalkyl, salt of a phosphonooxyalkyl, (alkylphosphooxy)alkyl, phosphorylalkyl, salt of a phosphorylalkyl, (alkylphosphoryl)alkyl, pyridinylalkyl, salt of a pyridinylalkyl, salt of a heteroarylalkyl and halogenated alkyl including polyhalogenated alkyl;

R 5 is selected from the group consisting of —C(═O)OR 6 , —C(═O)SR 6 , —C(═O)NR 6 R 6 and —C(═O)Z;

each R 6 can be independently selected from the group consisting of hydrogen, halogen, or substituted or unsubstituted variants of the following: C 1 -C 24 alkyl, acyl, alkylacyl, arylacyl, aryl, arylalkyl, p-nitrophenyl, pentafluorophenyl, pentafluoroethyl, trifluoroethyl, trichloroethyl, and heteroaryl;

R A and R B are each independently selected from the group consisting of substituted or unsubstituted variants of the following: C 1-6 alkyl, C 2-6 alkenyl and C 2-6 alkynyl, wherein R A and R B can be optionally bound together to form an optionally substituted 5, 6, 7, or 8 membered heterocyclyl;

Y is oxygen or sulfur;

Z is a halogen; and

PG 1 and PG 3 are each a protecting group moiety.

2. The method of claim 1 , further comprising substituting the primary hydroxy group of the compound of formula (XV) to form a compound of formula (XVI), wherein the compound of formula (XVI) has the following structure:

wherein X is a halogen.

3. The method of claim 1 , further comprising substituting the primary hydroxy group of the compound of formula (XV) to form a compound of formula (XVI-B), wherein the compound of formula (XVI-B) has the following structure:

wherein X is a halogen.

4. The method of claim 3 , further comprising the steps of:

(1) oxidizing the secondary hydroxy group of the compound of formula (XVI-B) wherein the compound of formula (XVI-B) has the following structure:

to form a compound of formula (XXII):

(2) reducing the keto group of the compound of formula (XXII) to form a compound of formula (XVI-A), wherein the compound of formula (XVI-A) has the following structure:

5. The method of claim 3 , further comprising the step of:

(1) inverting the stereochemistry of the secondary hydroxy carbon center of the compound of formula (XVI-B), wherein the compound of formula (XVI-B) has the following structure:

to form a compound of formula (XVI-A), wherein the compound of formula (XVI-A) has the following structure:

6. The method claim 1 , wherein PG 1 and PG 2 are each independently selected from the group consisting of benzyl, a substituted benzyl, an alkylcarbonyl, an arylalkylcarbonyl, a substituted methyl ether, a substituted ethyl ether, a substituted benzyl ether, a tetrahydropyranyl ether, a silyl ether, an ester, and a carbonate.

7. The method claim 1 , wherein the organometallic moiety is selected form the group consisting of an organomagnesium compound, an organolithium compound, an organotin compound, an organocuprates compound, organozinc compound, organoboron compound, and an organopalladium compound, a metal carbonyl, a metallocene, a carbine complex, and an organometalloid.

8. The of method claim 1 , wherein:

the organometallic moiety is selected from the group consisting of R 4 —MgR 7 , R 4 —ZnR 7 , —Li, (R 4 ) p —B(R 7 ) 3-p , and (R 4 ) q —Sn(R 7 ) 4-q ;

R 7 is selected from the group consisting of halogen, or substituted or unsubstituted variants of the following: alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, isopinocampheyl, hydroxy, alkoxy, and carbonylalkoxy, wherein if more than one R 7 is present, the R 7 groups can optionally be bond together to form an optionally substituted cycloalkyl, cycloalkenyl, heteroalkyl or heteroalkenyl ring;

p is an integer from 1 to 3; and

q is an integer from 1 to 4.

9. The method of claim 1 wherein R 4 is 2-cyclohexenyl.

10. The method of claim 1 wherein R 3 is methyl.

11. The method of claim 1 wherein R 5 is —C(═O)OR 6 ; and R 6 is hydrogen or substituted or unsubstituted C 1 -C 24 alkyl.

12. The method of claim 1 wherein R 5 is —C(═O)Z; and Z is a halogen.

13. A method of forming a compound of formula (X) from a compound of formula (V) comprising the steps of:

cleaving the carbon-carbon double bond of the compound of formula (V) and cyclizing the cleaved double bond with the tertiary hydroxy group;

transforming —COOR 2 to an aldehyde, wherein R 2 is selected from the group consisting of hydrogen, or substituted or unsubstituted variants of the following: C 1-6 alkyl, aryl, and arylalkyl; and

adding R 4 to the aldehyde using an organometallic moiety containing at least one R 4 , wherein R 4 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 2 -C 12 alkynyl, C 3 -C 12 cycloalkyl, C 3 -C 12 cycloalkenyl, C 3 -C 12 cycloalkynyl, C 3 -C 12 heterocyclyl, aryl, heteroaryl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, (heterocyclyl)alkyl, acyl, acylalkyl, alkyloxycarbonyloxy, carbonylacyl, aminocarbonyl, azido, azidoalkyl, aminoalkyl, salt of an aminoalkyl, carboxyalkyl, salt of carboxyalkyl, alkylaminoalkyl, salt of an alkylaminoalkyl, dialkylaminoalkyl, salt of a dialkylaminoalkyl, phenyl, alkylthioalkyl, arylthioalkyl, carboxy, cyano, alkanesulfonylalkyl, alkanesulfinylalkyl, alkoxysulfinylalkyl, thiocyanoalkyl, boronic acidalkyl, boronic esteralkyl, guanidinoalkyl, salt of a guanidinoalkyl, sulfoalkyl, salt of a sulfoalkyl, alkoxysulfonylalkyl, sulfooxyalkyl, salt of a sulfooxyalkyl, alkoxysulfonyloxyalkyl, phosphonooxyalkyl, salt of a phosphonooxyalkyl, (alkylphosphooxy)alkyl, phosphorylalkyl, salt of a phosphorylalkyl, (alkylphosphoryl)alkyl, pyridinylalkyl, salt of a pyridinylalkyl, salt of a heteroarylalkyl and halogenated alkyl including polyhalogenated alkyl.

14. A method of forming a compound of formula (XVII) from a compound of formula (V) comprising the steps of:

cleaving the carbon-carbon double bond of the compound of formula (V) and cyclizing the cleaved double bond with the tertiary hydroxy group; and

adding R 4 after cyclization with the tertiary hydroxy group using an organometallic moiety containing at least one R 4 , wherein R 4 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1 -C 12 alkyl, C 2 -C 12 alkenyl, C 2 -C 12 alkynyl, C 3 -C 12 cycloalkyl, C 3 -C 12 cycloalkenyl, C 3 -C 12 cycloalkynyl, C 3 -C 12 heterocyclyl, aryl, heteroaryl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, (heterocyclyl)alkyl, acyl, acylalkyl, alkyloxycarbonyloxy, carbonylacyl, aminocarbonyl, azido, azidoalkyl, aminoalkyl, salt of an aminoalkyl, carboxyalkyl, salt of carboxyalkyl, alkylaminoalkyl, salt of an alkylaminoalkyl, dialkylaminoalkyl, salt of a dialkylaminoalkyl, phenyl, alkylthioalkyl, arylthioalkyl, carboxy, cyano, alkanesulfonylalkyl, alkanesulfinylalkyl, alkoxysulfinylalkyl, thiocyanoalkyl, boronic acidalkyl, boronic esteralkyl, guanidinoalkyl, salt of a guanidinoalkyl, sulfoalkyl, salt of a sulfoalkyl, alkoxysulfonylalkyl, sulfooxyalkyl, salt of a sulfooxyalkyl, alkoxysulfonyloxyalkyl, phosphonooxyalkyl, salt of a phosphonooxyalkyl, (alkylphosphooxy)alkyl, phosphorylalkyl, salt of a phosphorylalkyl, (alkylphosphory)alkyl, pyridinylalkyl, salt of a pyridinylalkyl, salt of a heteroarylalkyl and halogenated alkyl including polyhalogenated alkyl.

15. A method for preparing a compound of formula (V) comprising performing an intramolecular aldol reaction on the compound of formula (IV) to form a compound of formula (V):

wherein:

R 1 is hydrogen or substituted or unsubstituted C 1-6 alkyl;

R 2 is selected from the group consisting of hydrogen, or substituted or unsubstituted variants of the following: C 1-6 alkyl, aryl, and arylalkyl; and

R 3 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1-6 alkyl, C 3-6 cycloalkyl, C 2-6 alkenyl, C 3-6 cycloalkenyl, aryl, and arylalkyl.

16. The method of claim 15 , wherein:

the compound of formula (IV) has the structure:

the compound of formula (V) has the structure:

17. The method of claim 15 , wherein:

the compound of formula (IV) has the structure:

the compound of formula (V) has the structure:

18. The method of claim 15 , wherein:

the compound of formula (IV) has the structure:

the compound of formula (V) has the structure:

19. The method of claim 15 , wherein:

the compound of formula (IV) has the structure:

the compound of formula (V) has the structure:

20. A method of preparing a compound of formula (VI) comprising cleaving the double bond of the compound of formula (V) and cyclizing the cleaved double bond with the tertiary hydroxy group to form a compound of formula (VI):

wherein:

R 1 is hydrogen or substituted or unsubstituted C 1-6 alkyl;

R 2 is selected from the group consisting of hydrogen, or substituted or unsubstituted variants of the following: C 1-6 alkyl, aryl, and arylalkyl; and

R 3 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1-6 alkyl, C 3-6 cycloalkyl, C 2-6 alkenyl, C 3-6 cycloalkenyl, aryl, and arylalkyl.

21. The method of claim 20 , wherein:

the compound of formula (V) has the structure:

and

the compound of formula (VI) has the structure:

22. The method of claim 20 , wherein:

the compound of formula (V) has the structure:

and

the compound of formula (VI) has the structure:

23. A compound of formula (V):

wherein:

R 1 is hydrogen or substituted or unsubstituted C 1-6 alkyl;

R 2 is selected from the group consisting of hydrogen, or substituted or unsubstituted variants of the following: C 1-6 alkyl, aryl, and arylalkyl; and

R 3 is selected from the group consisting of substituted or unsubstituted variants of the following: C 1-6 alkyl, a C 3-6 cycloalkyl, a C 2-6 alkenyl, C 3-6 cycloalkenyl, aryl, and arylalkyl.

24. The compound of claim 23 , wherein the compound of formula (V) has the structure:

25. The compound of claim 23 , wherein the compound of formula (V) has the structure:

26. The compound of claim 23 , wherein the compound of formula (V) has the structure:

27. The compound of claim 23 , wherein the compound of formula (V) has the structure: