Dienophilic reactivity of 2-phosphaindolizines: a conceptual DFT investigation

• Nosheen Beig,
• Aarti Peswani and
• Raj Kumar Bansal

Beilstein J. Org. Chem. 2022, 18, 1217–1224, doi:10.3762/bjoc.18.127

• ) calculations have been used in recent years to predict the reactivity of organic molecules in reactions. We calculated global hardness (η), global softness (S), electronic chemical potential (μ), electrophilicity (ω), and nucleophilicity (N) indices of four classes of 2-phosphaindolizines, on the basis of

• reactivities observed experimentally. Furthermore, energies and symmetries of the lowest unoccupied molecular orbitals (LUMO) of 2-phosphaindolizines were found to be in conformity with their dienophilic reactivities. Keywords: dienophilic reactivity; electronic chemical potential; electrophilicity index

• ; Fukui function; global hardness; nucleophilicity index; 2-phosphaindolizines; Introduction In 1988, we developed a simple synthetic method for the synthesis of 1,3-azaphospholo[1,5-a]pyridine derivative (1, R1 = Me, R2 = PhCO) from the reaction of 2-ethyl-1-phenacylpyridinium bromide with PCl3 and Et3N

Asymmetric Diels–Alder reaction with >C=P– functionality of the 2-phosphaindolizine-η¹-P-aluminium(O-menthoxy) dichloride complex: experimental and theoretical results

• Rajendra K. Jangid,
• Nidhi Sogani,
• Neelima Gupta,
• Raj K. Bansal,
• Moritz von Hopffgarten and
• Gernot Frenking

Beilstein J. Org. Chem. 2013, 9, 392–400, doi:10.3762/bjoc.9.40

• theoretically as well as experimentally [16]. In this context, we found that 1,3-bis(alkoxycarbonyl)-2-phosphaindolizines (1a, Z = CO2R1) prepared through 1,5-electrocyclization of in situ generated bis(pyridinium ylidyl)phosphenium chlorides [17] lead to successful DA reaction [18][19], but 3-alkoxycarbonyl-2

• -menthoxy) dichloride, the transition structures, and the products optimized at the B3LYP/6-31+G* level in the gas-phase. The relative activation and reaction energies obtained in methylene chloride are given in parentheses. Diels–Alder reaction of 2-phosphaindolizines. Diels–Alder reaction of 2

• -phosphaindolizines having an electron-withdrawing group (EWG) only at the 3-position (1b, Z = Me) failed to undergo DA reaction even on heating under reflux in toluene alone or in the presence of sulfur [18] (Scheme 1). It was demonstrated that the dienophilic reactivity of the >C=P– functionality of phosphinines