Periodic Reporting for period 1 - TripIod (Development of Triptycene-Based New Hypervalent Iodine Reagents for Selective Organic Synthesis)
Okres sprawozdawczy: 2019-04-04 do 2021-04-03
Initially, we prepared triptycene core structure bearing iodine at position–1 or –2 in one of the aromatic rings. Subsequently, chiral iodotriptycene compounds such as 1–chloro–7–iodotriptycene and 5-iodo-1,4-dimethoxytriptycene have been prepared and their enantiomers were separated and isolated using preparative chiral HPLC method and chiral resolution method. The absolute configuration of each of the isolated enantiomers of 5-iodo-1,4-dimethoxytriptycene was determined by single crystal X-ray structures having a high HPLC purity. Prepared iodotriptycenes were investigated in a catalytic manner for the α-oxytosylation of propiophenone, yields were good but enantioselectivities was generally not high.
1. To developed a strategy to prepare novel iodotriptycene reagents and use of 1,4-dimethoxyanthracene to avoid diastereomers formation.
2. To investigate activity of iodotriptycenes as a catalysts in organic transformations of α–oxytosylation of propiophenone.
3. To use enantiomers of 1-chloro-7-iodotriptycene and 5–iodo–1,4–dimethoxytriptycene in stereoselective reactions of α-oxytosylation of propiophenone.
4. To use iodotriptyce in making 2-(diacetoxyiodo)-triptycene and to utilize 5–iodo–1,4–dihydroxytriptycene in polymer synthesis.
5. To use iodotriptycene in flow electrochemistry by oxidizing it with electric current.
6. To train Dr. Khan with skills required for enantioselective reactions that previously he has not been experienced including hands on experience for electrochemistry in flow and non-scientific training.
We have prepared “iodotriptycenes” including their chiral analogues whose core structure possesses features to show non-covalent interactions. They show good catalytic activity in organic transformation of α-oxytosylation of propiophenone but with low enantioselectivity. In the area of hypervalent iodine chemistry these are promising new catalyst. Developed new methods would be useful informations in making chiral triptycene compounds in material chemistry, polymer chemistry or in supramolecular chemistry and non-metal triptycene based catalyst.
We have established a reliable approach for the synthesis of iodotriptycenes and their chiral analogues and are proven efficient new metal free catalyst in organic transformations (eg. α-oxytosylation). Although enantioinduction of these new chiral iodotriptycene catalysts are generally low, we hope this work serves as a basis for further research in this area, which is key for progression.
1. To developed a strategy to prepare novel iodotriptycene reagents and use of 1,4-dimethoxyanthracene to avoid diastereomers formation.
2. To investigate activity of iodotriptycenes as a catalysts in organic transformations of α–oxytosylation of propiophenone.
3. To use enantiomers of 1-chloro-7-iodotriptycene and 5–iodo–1,4–dimethoxytriptycene in stereoselective reactions of α-oxytosylation of propiophenone.
4. To use iodotriptyce in making 2-(diacetoxyiodo)-triptycene and to utilize 5–iodo–1,4–dihydroxytriptycene in polymer synthesis.
5. To use iodotriptycene in flow electrochemistry by oxidizing it with electric current.
6. To train Dr. Khan with skills required for enantioselective reactions that previously he has not been experienced including hands on experience for electrochemistry in flow and non-scientific training.
We have prepared “iodotriptycenes” including their chiral analogues whose core structure possesses features to show non-covalent interactions. They show good catalytic activity in organic transformation of α-oxytosylation of propiophenone but with low enantioselectivity. In the area of hypervalent iodine chemistry these are promising new catalyst. Developed new methods would be useful informations in making chiral triptycene compounds in material chemistry, polymer chemistry or in supramolecular chemistry and non-metal triptycene based catalyst.
We have established a reliable approach for the synthesis of iodotriptycenes and their chiral analogues and are proven efficient new metal free catalyst in organic transformations (eg. α-oxytosylation). Although enantioinduction of these new chiral iodotriptycene catalysts are generally low, we hope this work serves as a basis for further research in this area, which is key for progression.
Triptycene scaffolds have largely been explored in supramolecular and polymer chemistry but not much known about their use as a reagent and catalyst. As triptycene–based hypervalent iodine reagents are currently unknown, we have synthesized iodotriptycene derivatives including chiral iodotriptycenes and have investigated their catalytic use in organic transformations for α–oxytosylation of propiophenone.
Our main target was to synthesize iodotriptycene compounds including chiral reagents and to explore their potential reactivity as a catalyst in selective organic transformations. Initially, we prepared triptycene core structure bearing iodine at position–1 or –2 in one of the aromatic rings (Schemes 1 and 2) and were fully characterised including X-ray structures. Both were investigated in a catalytic manner (10 mol%) for the α-oxytosylation of propiophenone (Scheme 6) and are efficient (Table 1, entries 1 and 2). A hypervalent iodotriptycene compound, 2-(diacetoxyiodo)-triptycene was also prepared (scheme 3).
Two different chiral iodotriptcenes were prepared (Schemes 4 and 5). Diastereomers syn-8 and anti-8 were separated using preparative TLC and their structures were confirmed by single crystal X-ray. Enantiomers of syn-8 separated by chiral HPLC methods were investigated in the α-oxytosylation of propiophenone (Scheme 6) but the enantioselectivities in the products were low (Table 1, entries 3 and 4).
As the position of iodine is not very close to the chiral center in syn-8, 5–iodo–1,4–dimethoxytriptycene was prepared using 1,4–dimethoxyanthracene that avoids the formation of diastereomers (Scheme 5). Initially, we planned to isolate the enantiomers of this compound 12 using chiral HPLC method but, could not performed it due to poor solubility in the solvent that was required for the separation. So, enantiomers of 12 were separated using chiral resolving agent (1S)-(–)-camphanic chloride. The absolute configuration of isolated enantiomers was determined by their single crystal X-ray structures as (9S,10S) – (–) –12 and (9R,10R)–(+)-12 and the optical rotations of these enantiomers were also determined. The HPLC purity was very good and the enantiomeric excess was >99%. These were investigated in the α–oxytosylation of propiophenone (Scheme 6) but the enantioselectivities in the products were low (Table 1, entries 5 and 6).
Conclusion: Established a reliable approach for the synthesis of iodotriptycenes ● Iodotriptycene works as a catalyst in organic transformations (eg. α-oxytosylation) ● Triptycene based hypervalent iodine compounds (eg. 2-(diacetoxyiodo)-triptycene) and chiral iodotriptycenes have been synthesized and investigated in an enantioselective reaction of α-oxytosylation of propiophenone.
We have synthesized different 1- and 2-iodotriptycenes including chiral iodotriptycenes. They are investigated in organic transformations of α-oxytosylation of propiophenone and are found efficient catalyst but generally with low enantioselectivity. Hypervalent iodotriptycene such as 2-(diacetoxyiodo)-triptycene has also been prepared. To the best of our knowledge this work shows a first oxidative iodotriptycene catalyst in organic synthesis. In addition, we have published a minireview on chiral triptycenes.
Our main target was to synthesize iodotriptycene compounds including chiral reagents and to explore their potential reactivity as a catalyst in selective organic transformations. Initially, we prepared triptycene core structure bearing iodine at position–1 or –2 in one of the aromatic rings (Schemes 1 and 2) and were fully characterised including X-ray structures. Both were investigated in a catalytic manner (10 mol%) for the α-oxytosylation of propiophenone (Scheme 6) and are efficient (Table 1, entries 1 and 2). A hypervalent iodotriptycene compound, 2-(diacetoxyiodo)-triptycene was also prepared (scheme 3).
Two different chiral iodotriptcenes were prepared (Schemes 4 and 5). Diastereomers syn-8 and anti-8 were separated using preparative TLC and their structures were confirmed by single crystal X-ray. Enantiomers of syn-8 separated by chiral HPLC methods were investigated in the α-oxytosylation of propiophenone (Scheme 6) but the enantioselectivities in the products were low (Table 1, entries 3 and 4).
As the position of iodine is not very close to the chiral center in syn-8, 5–iodo–1,4–dimethoxytriptycene was prepared using 1,4–dimethoxyanthracene that avoids the formation of diastereomers (Scheme 5). Initially, we planned to isolate the enantiomers of this compound 12 using chiral HPLC method but, could not performed it due to poor solubility in the solvent that was required for the separation. So, enantiomers of 12 were separated using chiral resolving agent (1S)-(–)-camphanic chloride. The absolute configuration of isolated enantiomers was determined by their single crystal X-ray structures as (9S,10S) – (–) –12 and (9R,10R)–(+)-12 and the optical rotations of these enantiomers were also determined. The HPLC purity was very good and the enantiomeric excess was >99%. These were investigated in the α–oxytosylation of propiophenone (Scheme 6) but the enantioselectivities in the products were low (Table 1, entries 5 and 6).
Conclusion: Established a reliable approach for the synthesis of iodotriptycenes ● Iodotriptycene works as a catalyst in organic transformations (eg. α-oxytosylation) ● Triptycene based hypervalent iodine compounds (eg. 2-(diacetoxyiodo)-triptycene) and chiral iodotriptycenes have been synthesized and investigated in an enantioselective reaction of α-oxytosylation of propiophenone.
We have synthesized different 1- and 2-iodotriptycenes including chiral iodotriptycenes. They are investigated in organic transformations of α-oxytosylation of propiophenone and are found efficient catalyst but generally with low enantioselectivity. Hypervalent iodotriptycene such as 2-(diacetoxyiodo)-triptycene has also been prepared. To the best of our knowledge this work shows a first oxidative iodotriptycene catalyst in organic synthesis. In addition, we have published a minireview on chiral triptycenes.
Chiral 5-iodo-1,4-dihydroxytriptycene intermediate could be a practical molecule in preparation of chiral polymers and chiral materials. Triptycene based iodonium salt could provide a new idea to utilize it in making functionalized triptycene derivatives including their chiral analogues.
Different 1- and 2-iodotriptycenes including chiral analogues have been synthesized and are investigated as efficient catalyst. But, enantioinduction of the catalysts are generally low. Hypervalent iodotriptycene compound 2-(diacetoxyiodo)-triptycene has also been synthesized.
Synthesized new iodotriptycenes including their chiral analogues are proven efficient non-metal catalyst and provides new informations. They could be applied in electrochemical flow reactions as part of technology development. Chiral intermediate 5–iodo–1,4–dihydroxytriptycene could be a useful substrate in making chiral materials and triptycene-based hypervalent iodine chiral polymers as a supported reagent in organic synthesis focusing on green chemistry. It is expected that postdoctoral researcher Dr. Md. Nasim Khan with new skills and knowledge gained by him with this project in iodine chemistry with triptycene molecule including non-scientific training would be transferrable to a large audience through his new collaboration, seminar presentation and through interaction with society and are a demonstrable contribution. This work shows a first oxidative iodotriptycene catalyst in organic synthesis and serves as a basis for further research in this area, which is key for progression.
Different 1- and 2-iodotriptycenes including chiral analogues have been synthesized and are investigated as efficient catalyst. But, enantioinduction of the catalysts are generally low. Hypervalent iodotriptycene compound 2-(diacetoxyiodo)-triptycene has also been synthesized.
Synthesized new iodotriptycenes including their chiral analogues are proven efficient non-metal catalyst and provides new informations. They could be applied in electrochemical flow reactions as part of technology development. Chiral intermediate 5–iodo–1,4–dihydroxytriptycene could be a useful substrate in making chiral materials and triptycene-based hypervalent iodine chiral polymers as a supported reagent in organic synthesis focusing on green chemistry. It is expected that postdoctoral researcher Dr. Md. Nasim Khan with new skills and knowledge gained by him with this project in iodine chemistry with triptycene molecule including non-scientific training would be transferrable to a large audience through his new collaboration, seminar presentation and through interaction with society and are a demonstrable contribution. This work shows a first oxidative iodotriptycene catalyst in organic synthesis and serves as a basis for further research in this area, which is key for progression.