Unusual addition reactions of lithium alkoxides to 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene

Abstract

published as an Advance Article on the web 2,4,6-Tri-tert-butyl-1,3,5-triphosphabenzene (1) reacts selectively with a mixture of the primary lithium alkoxides 2a,b and the corresponding alcohols 3a,b to afford the novel 2,4,6-tri-tert-butyl-1,3,5-alkoxy-1,3,5-triphosphacyclohexane derivatives 4a,b; treatment of 4a with sulfur results in oxidation of all phosphorus atoms to furnish the triphosphane sulfide 5.

Highly unsaturated phosphorus compounds: Trimeric and dimeric sulfides of a α,β‐di‐tert‐butyl vinyl phosphaalkyne

“…A stable sulfide of aromatic‐substituted monophosphinine 1 was recently isolated 4. In contrast to aromatic‐substituted systems, attempts to prepare sulfides of alkyl‐substituted triphosphabenzenes did not preserve the aromatic system 5. To date, the mono‐, di‐, and trisulfides of alkyl‐substituted triphosphobenzenes 3 – 5 remain elusive (Fig.…”

“… Structures of stable sulfide of monophosphinine 1 , α,β‐di‐ tert ‐butyl vinyl 1,3,5‐triphosphinine 2 , and mono‐, di‐, and trisulfides of triphosphabenzenes 3–4 . …”

New Phosphorus−Carbon Cage Compounds by Diels−Alder and Homo Diels−Alder Reactions of 1,3,5-Triphosphabenzenes with Alkenes

“…[2] Shortly thereafter, a simple one-pot synthesis was developed that also made the isolation of other triphosphabenzene derivatives possible. [3] Although their physicochemical properties (NMR spectroscopic data, [2,3] crystal structure analysis [4] ) as well as theoretical investigations [5] clearly demonstrate the aromatic character of the 1,3,5-triphosphabenzenes 1, the compounds exhibit a surprisingly high reactivity in, for example, 1,2-additions [6] or [4 ϩ 2] cycloaddition reactions. [7] Thus, alcohols undergo addition to the PϪC double bond in alkaline media to furnish the 1,3,5-trialkyloxy-1,3,5-triphosphinanes 4, [6] while alkynes 5 react to afford the novel triphospha cage compounds 7 through a DielsϪAlder/ homo DielsϪAlder reaction sequence (Scheme 1) with the 1,3,5-triphosphabicyclo[2.2.2]octa-2,5,7-trienes 6 as intermediates.…”

1,4‐Addition of Grignard Reagents to 2,4,6‐Tri‐tert‐butyl‐1,3,5‐triphosphabenzene

“…Although triphosphabenzenes, for example, 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene (1) [3] exhibit a marked aromatic character according to physical-chemical measurements, [4] they are in fact highly reactive compounds. Thus, for example, DielsAlder reactions [5] or addition reactions of lithium alkoxides with participation of all three PÀC double bonds [6] occur readily under mild conditions. Compound 1 also reacts readily with silylenes, [7] carbenes, [8] or phosphinidenes, [9] usually through a [2þ1]-cycloaddition process.…”