Stereoelectronic Effects in Force-Accelerated Retro-Diels–Alder Reactions

Abstract

In polymer mechanochemistry, mechanosensitive molecules (mechanophores) are activated upon elongation of anchored polymer arms. The reactivity of a mechanophore can be influenced by a variety of structural factors, including the geometry of attachment of the polymer arms and the nature of eventual substituents. Here we investigate stereoelectronic effects in force-accelerated Diels–Alder reactions using the CoGEF (Constrained Geometries simulate External Force) calculation method. We found that the presence of an electron-donating heteroatom on the diene leads to a lower activation force, and that the mechanochemical reactivity is suppressed when the anchor group is attached to a central rather than lateral position.

Key words

polymer mechanochemistry - mechanophore - force - Diels–Alder - retrocycloaddition - Hammett parameter

Publication History

Received: 05 February 2022

Accepted after revision: 15 March 2022

Accepted Manuscript online:
15 March 2022

Article published online:
06 May 2022

• References and Notes

• 1a O’Neill RT, Boulatov R. Nat. Rev. Chem. 2021; 5: 148
• 1b De Bo G. Macromolecules 2020; 53: 7615
• 1c Caruso MM, Davis DA, Shen Q, Odom SA, Sottos NR, White SR, Moore JS. Chem. Rev. 2009; 109: 5755
• 2 Stevenson R, De Bo G. J. Am. Chem. Soc. 2017; 139: 16768
• 3a Noh J, Peterson GI, Choi T. Angew. Chem. Int. Ed. 2021; 60: 18651
• 3b Peterson GI, Lee J, Choi T.-L. Macromolecules 2019; 52: 9561
• 3c Lin Y, Zhang Y, Wang Z, Craig SL. J. Am. Chem. Soc. 2019; 141: 10943
• 3d Church DC, Peterson GI, Boydston AJ. ACS Macro Lett. 2014; 3: 648
• 3e Zhang H, Diesendruck C. Angew. Chem. Int. Ed. 2022; 61: e202115325
• 4a Stevenson R, Zhang M, De Bo G. Polym. Chem. 2020; 11: 2864
• 4b Wang J, Kouznetsova TB, Kean ZS, Fan L, Mar BD, Martinez TJ, Craig SL. A. J. Am. Chem. Soc. 2014; 136: 15162
• 4c Klukovich HM, Kouznetsova TB, Kean ZS, Lenhardt JM, Craig SL. A. Nat. Chem. 2013; 5: 110
• 4d Tian Y, Boulatov R. ChemPhysChem 2012; 13: 2277
• 4e Klukovich HM, Kean ZS, Ramirez AL. B, Lenhardt JM, Lin J, Hu X, Craig SL. J. Am. Chem. Soc. 2012; 134: 9577
• 5a Brown CL, Bowser BH, Meisner J, Kouznetsova TB, Seritan S, Martinez TJ, Craig SL. J. Am. Chem. Soc. 2021; 143: 3846
• 5b Nixon R, De Bo G. Nat. Chem. 2020; 12: 826
• 5c Lin Y, Craig SL. Chem. Sci. 2020; 11: 10444
• 5d Barbee MH, Kouznetsova T, Barrett SL, Gossweiler GR, Lin Y, Rastogi SK, Brittain WJ, Craig SL. J. Am. Chem. Soc. 2018; 140: 12746
• 5e Kryger MJ, Munaretto AM, Moore JS. J. Am. Chem. Soc. 2011; 133: 18992
• 6a Wang Z, Craig SL. Chem. Commun. 2019; 50: 2836
• 6b Zhang H, Li X, Lin Y, Gao F, Tang Z, Su P, Zhang W, Xu Y, Weng W, Boulatov R. Nat. Commun. 2017; 8: 1147
• 6c Wang J, Kouznetsova TB, Craig SL. J. Am. Chem. Soc. 2015; 137: 11554
• 6d Kean ZS, Niu Z, Hewage GB, Rheingold AL, Craig SL. J. Am. Chem. Soc. 2013; 135: 13598
• 6e Lenhardt JM, Ong MT, Choe R, Evenhuis CR, Martinez TJ, Craig SL. Science 2010; 329: 1057
• 7a Lin Y, Barbee MH, Chang C.-C, Craig SL. J. Am. Chem. Soc. 2018; 140: 15969
• 7b Kim TA, Robb MJ, Moore JS, White SR, Sottos NR. Macromolecules 2018; 51: 9177
• 7c Robb MJ, Kim TA, Halmes AJ, White SR, Sottos NR, Moore JS. J. Am. Chem. Soc. 2016; 138: 12328
• 7d Gossweiler GR, Kouznetsova TB, Craig SL. J. Am. Chem. Soc. 2015; 137: 6148
• 7e Konda SS. M, Brantley JN, Varghese BT, Wiggins KM, Bielawski CW, Makarov DE. J. Am. Chem. Soc. 2013; 135: 12722
• 8a Zhang M, De Bo G. J. Am. Chem. Soc. 2020; 142: 5029
• 8b Zhang M, De Bo G. J. Am. Chem. Soc. 2019; 141: 15879
• 8c Zhang M, De Bo G. J. Am. Chem. Soc. 2018; 140: 12724
• 9 Nixon R, De Bo G. J. Am. Chem. Soc. 2021; 143: 3033
• 10a Beyer M. J. Chem. Phys. 2000; 112: 7307

For recent reviews, see:
• 10b Ribas-Arino J, Marx D. Chem. Rev. 2012; 112: 5412
• 10c Stauch T, Dreuw A. Chem. Rev. 2016; 116: 14137
• 10d Klein IM, Husic CC, Kovács DP, Choquette NJ, Robb MJ. J. Am. Chem. Soc. 2020; 142: 16364
• 11 McDaniel DH, Brown HC. J. Org. Chem. 1958; 23: 420

The release of singlet oxygen (see ref. 13a) has been achieved recently using a similar flex-activation mechanism (see ref. 13b):
• 12a Turksoy A, Yildiz D, Aydonat S, Beduk T, Canyurt M, Baytekin B, Akkaya EU. RSC Adv. 2020; 10: 9182
• 12b Larsen MB, Boydston AJ. J. Am. Chem. Soc. 2013; 135: 8189
• 13 Izak-Nau E, Campagna D, Baumann C, Göstl R. Polym. Chem. 2020; 11: 2274
• 14 For a computational mechanistic study of force-accelerated rDA reaction, discussing the synchronicity of the process, see: Cardosa-Gutierrez M, De Bo G, Duwez A.-S, Remacle F. ChemRxiv 2022; preprint