Traceless directing groups in radical cascades: from oligoalkynes to fused helicenes without tethered initators

Patent metadata

Field	Value
Publication number	US-2016145276-A1
Application number	US-201514930860-A
Country	US
Kind code	A1
Filing date	Nov 3, 2015
Priority date	Nov 24, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

The present disclosure is directed to a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by a propargyl alkoxy moiety. Radical translocations lead to the boomerang return of radical center to the site of initial attack where it assists to the elimination of the directing functionality via β-scission in the last step of the cascade. In some aspects, the reaction of the present invention is catalyzed by a stannane moiety, which allows further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions.

First claim

What is claimed is:

1 . A method of preparing a polycyclic aromatic compound, the method comprising:
contacting a compound having structure (I) with a stannane compound in the presence of a radical initiator to thereby prepare the polycyclic aromatic compound; wherein the polycyclic aromatic compound has a structure (1-a) as follows:

wherein the compound having structure (I) is as follows:

and further wherein:
each R is independently selected from the group consisting of hydrogen, halogen, cyano, C 1 -C 6 alkyl, and C 1 -C 6 alkoxy;
R 1 is selected from the group consisting of C 1 -C 6 alkyl, —CH 2 OCH 3 , and —CH 2 CH 2 OCH 3 ;
X is a C 1 -C 6 alkyl or phenyl;
n 1 and n 2 each independently have a value between 0 and 50, and further wherein either n 1 and n 2 have the same value or n 1 =n 2 +1; and
n 3 has a value of n 1 +n 2 .

2 . The method of claim 1 wherein the stannane compound is selected from the group consisting of trimethyl stannane, triethyl stannane, tri(n-propyl)stannane, tri(isopropyl)stannane, tri(n-butyl)stannane, tri(isobutyl)stannane, triphenyl stannane, and any combination there.

3 . The method of claim 1 wherein the stannane compound is tri(n-butyl)stannane.

4 . The method of claim 1 wherein the radical initiator is selected from the group consisting of an azo compound, an inorganic peroxide, an organic peroxide, and any combination thereof.

5 . The method of claim 1 wherein R 1 is methyl.

6 . The method of claim 1 wherein n 1 and n 2 each independently have a value between 0 and 25, and further wherein n 1 and n 2 have the same value.

7 . The method of claim 1 wherein n 1 and n 2 each independently have a value between 0 and 25, and further wherein n 1 =n 2 +1.

8 . The method of claim 1 further comprising contacting the polycyclic aromatic compound having structure (1-a) with an acid to thereby prepare a polycyclic aromatic compound having structure (1-b):

wherein R and N 3 are as defined in claim 1 .

9 . The method of claim 1 wherein the polycyclic aromatic compound having structure (1-a) has the following structure (1-c):

wherein R and X are as defined in claim 1 .

10 . The method of claim 9 further comprising contacting the polycyclic aromatic compound having structure (1-c) with an acid to thereby prepare a polycyclic aromatic compound having structure (1-d):

wherein R is as defined in claim 1 .

11 . The method of claim 1 wherein the polycyclic aromatic compound having structure (1-a) has the following structure (1-e):

wherein R and X are as defined in claim 1 .

12 . The method of claim 11 further comprising contacting the polycyclic aromatic compound having structure (1-e) with an acid to thereby prepare a polycyclic aromatic compound having structure (1-f):

wherein R is as defined in claim 1 .

13 . A method of preparing a polycyclic aromatic compound, the method comprising:
contacting a compound having structure (II) with a stannane compound in the presence of a radical initiator to thereby prepare the polycyclic aromatic compound; wherein the polycyclic aromatic compound has a structure (1-g) as follows:

wherein the compound having structure (II) is as follows:

and further wherein:
each R is independently selected from the group consisting of hydrogen, halogen, cyano, C 1 -C 6 alkyl, and C 1 -C 6 alkoxy;
R 1 is selected from the group consisting of C 1 -C 6 alkyl, —CH 2 OCH 3 , and —CH 2 CH 2 OCH 3 ;
X is a C 1 -C 6 alkyl or phenyl;
n 1 and n 2 each independently have a value between 0 and 50, and further wherein either n 1 and n 2 have the same value or n 1 =n 2 +1; and
n 3 has a value of n 1 +n 2 .

14 . The method of claim 13 wherein the stannane compound is selected from the group consisting of trimethyl stannane, triethyl stannane, tri(n-propyl)stannane, tri(isopropyl)stannane, tri(n-butyl)stannane, tri(isobutyl)stannane, triphenyl stannane, and any combination there.

15 . The method of claim 13 wherein the stannane compound is tri(n-butyl)stannane.

16 . The method of claim 13 wherein the radical initiator is selected from the group consisting of an azo compound, an inorganic peroxide, an organic peroxide, and any combination thereof.

17 . The method of claim 13 further comprising contacting the polycyclic aromatic compound having structure (1-g) with an acid to thereby prepare a polycyclic aromatic compound having structure (1-h):

wherein R and N 3 are as defined in claim 1 .

18 . A method of preparing a polycyclic aromatic compound, the method comprising:
contacting a compound having structure (III) with a stannane compound in the presence of a radical initiator to thereby prepare the polycyclic aromatic compound; wherein the polycyclic aromatic compound has a structure (2-a) as follows:

wherein the compound having structure (III) is as follows:

and further wherein:
A 1 , A 2 , A 3 , and A 4 are either C—R or N, wherein at least two of A 1 , A 2 , A 3 , and A 4 are C—R, and each R is independently selected from the group consisting of hydrogen, halogen, C 1 -C 6 alkyl, and C 1 -C 6 alkoxy;
B 1 , B 2 , B 3 , and B 4 are either C—R or N, wherein at least two of B 1 , B 2 , B 3 , and B 4 are C—R, and each R is independently selected from the group consisting of hydrogen, halogen, C 1 -C 6 alkyl, and C 1 -C 6 alkoxy;
C 1 and C 2 are either C—R or N, and each R is independently selected from the group consisting of hydrogen, halogen, C 1 -C 6 alkyl, and C 1 -C 6 alkoxy;
R 1 is selected from the group consisting of C 1 -C 6 alkyl, —CH 2 OCH 3 , and —CH 2 CH 2 OCH 3 ;
R 2 , R 3 , and R 4 are each independently selected from the group consisting of hydrogen, halogen, cyano, nitro, C 1 -C 6 -alkyl, C 1 -C 6 alkoxy, hydroxy-C 1 -C 6 -alkyl, halo-C 1 -C 6 -alkyl, cyano-C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy-C 1 -C 6 -alkyl, C 1 -C 6 -alkylcarbonyl, C 1 -C 6 -alkoxycarbonyl, C 1 -C 6 -alkoxycarbonyl-C 1 -C 6 -alkyl, C 3 -C 6 -cycloalkyl, C 3 -C 6 -cycloalkyl-C 1 -C 6 -alkyl, C 5 -C 10 -cycloalkenyl, aryl, aryl-C 1 -C 6 -alkyl, 4- to 10-membered ring heterocyclyl, 4- to 10-me

Assignees

• Univ Florida State Res Found

Inventors

• Alabugin Igor V
• Pati Kamalkishore

Classifications

• C07C2603/54

  containing more than five condensed rings · CPC title

• C07C2603/40

  containing four condensed rings · CPC title

• C07C253/30

  by reactions not involving the formation of cyano groups · CPC title

• C07C41/18

  by reactions not forming ether-oxygen bonds · CPC title

• C07D317/70

  condensed with ring systems containing two or more relevant rings · CPC title