Four consecutive reactions in one pot: cascade formation of an unprecedented triphosphatricyclo[3.2.1.0^2,7]oct-3-ene

Abstract

Di-pyrone 2H,2′H-[3,3′-bipyran]-2,2′-dione undergoes four consecutive pericyclic reactions with (CH3)3Si-CP to form an unprecedented chiral cage compound triphosphatricyclo[3.2.1.02,7]oct-3-ene in high yield.

A new access to diazaphospholes via cycloaddition–cycloreversion reactions on triazaphospholes

“…This level of theory was used successfully for cycloaddtion reactions before. 14 The concerted cycloaddition-cycloreversion process (Fig. 2, Chart 2 and ESI †) is in full agreement with all experimental observations.…”

Understanding the Mechanism of Diels–Alder Reactions with Anionic Dienophiles: A Systematic Comparison of [ECX]− (E = P, As; X = O, S, Se) Anions

“… 45 Recently, the cycloaddition using the trimethylsilyl analogue (TMS-C≡P) enabled synthetic access to biphosphinines (P analogues of bipyridine) and phosphaanilines. 46 , 47 …”

“…Not only can the parent 2-phosphaphenolate anion , be obtained from [PCO] − and 2 H -pyran-2-one but further heavily substituted analogues have also been reported, showing the functional group tolerance of this reaction. , Importantly, these versatile 2-phosphaphenols have been utilized as ligands toward Cu I and Au I centers, and they also allow for the synthesis of neutral chelating ligand systems for transition metals in low oxidation states (e.g., Cu I , Pd II , and Rh I ). − Not surprisingly, the cycloaddition reactions of the [PCO] − anion clearly resemble those of phosphaalkynes (R-CP), which have also become useful synthons in organophosphorus chemistry during the last decades, well-documented by the rich chemistry of the tert -butyl analogue, t BuCP. − The reactions of phosphaalkynes with pyrones, leading to phosphabenzenes, are also known . Recently, the cycloaddition using the trimethylsilyl analogue (TMS-CP) enabled synthetic access to biphosphinines (P analogues of bipyridine) and phosphaanilines. , …”

“…45 Recently, the cycloaddition using the trimethylsilyl analogue (TMS-CP) enabled synthetic access to biphosphinines (P analogues of bipyridine) and phosphaanilines. 46,47 Several heavier congeners of the [PCO] − anion are also known, however, to a much lesser extent. Among these, the [PCS] − anion (the P analogue of the thiocyanate ion) was reported as a lithium salt by Becker and Hubler almost 3 decades ago.…”