Adducts of the Parent Boraphosphaketene H₂BPCO and their Decarbonylative Insertion Chemistry

Abstract

The first examples of Lewis base adducts of the parent boraphosphaketene (H 2 B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a BÀC bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their p complexes with the Group 6 metals. Figure 1. Top: phosphaketenes and their decarbonylation chemistry. Bottom: boron-functionalized phosphaketenes and their phosphaethynolate constitutional isomers.

Recent Advances in the Domain of Cyclic (Alkyl)(Amino) Carbenes

“…[151] stabilized boraphosphaketenes (85 and 86) by nucleophilic addition of cAAC-stabilized triflatoboranes to sodium phosphaethynolate anion. [152] On storing at À 30 °C, 85 gets converted into dimeric form, while 86 transforms into dimeric form while drying, washing, and crystallizing. The dimeric forms of cAAC-stabilized boraphosphaketenes (87 and 88) were characterized by single-crystal XRD (Scheme 37).…”

Recent advances in the chemistry of the phosphaethynolate and arsaethynolate anions

“…Recently, Braunschweig and co-workers reported the synthesis of the first unprecedented adducts of the parent boraphosphaketene (H 2 B–PCO) and further examined its reactivity via decarbonylative insertion processes. 45 Initially, a mixture of [(CAAC R )BH 2 (OTf)] (CAAC = cyclic alkyl(amino)carbene; CAAC R = CAAC Me ( 37a ), CAAC Cy ( 37b )) and [Na(dioxane) x ](OCP) resulted in unstable boraphosphaketenes [(CAAC R )BH 2 (PCO)] (CAAC R = CAAC Me ( 38a ); CAAC Cy ( 38b )) at room temperature (Scheme 15), displaying 31 P NMR resonance at δ = −337 ( 38a ) and −339 ( 38b ) ppm. Compound 38a was isolated as a yellow solid in good yield.…”

Addukte des Stammboraphosphaketens H2BPCO und deren Insertionsreaktionen mittels Decarbonylierung

“…Solch eine Bande fehlt im IR-Spektrum von Goicoecheas Boraphosphaethinolat, [8c] während für die Verbindung von Wilson und Gilliard keine IR-spektroskopischen Daten angegeben wurden. [8d] Das Dublett im 13 [21] Schwingungsellipsoide entsprechen einer Aufenthaltswahrscheinlichkeit von 50 %. Ellipsoide der Ligandenperipherie und alle bis auf Bor-gebundene Wasserstoffatome wurden nicht dargestellt.…”

“…Rechts eingefügt: Kristallographisch ermittelte Festkçrperstrukturen von 4 a und 5 a. [21] Schwingungsellipsoide entsprechen einer Aufenthaltswahrscheinlichkeit von 50 %. Ellipsoide der Ligandenperipherie und alle bis auf Bor-gebundene Wasserstoffatome wurden nicht dargestellt.…”

“…Oben: Synthese der CAAC-stabilisierten Boraphosphaketene 2 a,b und deren Dimere 3 a,b. Unten: Kristallographisch ermittelte Festkçrperstruktur von 3 a,b [21]. Schwingungsellipsoide entsprechen einer Aufenthaltswahrscheinlichkeit von 50 %.…”