Dibenzo phosphorins

The reaction of the stannane (176) with phosphorus trichloride gives the phosphorin (177). The electron-donating methyl group reinforces the ring dipole, the negative end of which is the phosphorus atom.189 The dibenzo analogue (178) has also been prepared and its electronic structure studied by photoelectron spectroscopy.160... 

In this manner de Koe, van Veen andBickelhaupt [33,34,35] were able to prepare the very unstable 9-phosphaphenanthrene 37 as well as 9-phospha-anthracene 41a, These compounds were stored in solution and could not be isolated as solids.However, if the C-10 position of 41 is blocked by a phenyl group, the same procedure leads to the much more stable yellow crystalline, 10-phenyl-9-phospha-anthracene 41b (4-phenyl-dibenzo[b, e]-phosphorin) (m. p. 173—176 °C). Another stable substituted phosphaphenanthrene 43 has been prepared (a/he/t in... 

Nach gleichem Reaktionsmuster lassen sich auch Dibenzophosphole mit Alkinen wie z.B. Propiolsaure-methylester umsetzen295. In diesem Falle liefert die apicale Substituenten-verdrangung 5,6-Dihydro-(dibenzo[b d]phosphorin)-5-oxide ... 

Methoxycarbonyl-methyl)- -methyl-5,6-dihydro-(dibenzo[b d] phosphorin)-5- osid 295 Zu 0,21 g (2,5 mmol) Propiolsaure-methylester in 5 ml THF und 0,2 ml Wasser gibt man innerhalb 10 Min. Lropfenweise die Losung von 0,5 g (2,7 mmol) 5-Methyl-dibenzOphosphol in 10m/ THF. AnschlieBend erhitzt man 12 Stdn. zum RiickfluB, dampft ein und kristallisiert den Riickstand aus Ether und Benzol Ausbeute 0,5 g (70°/o) Schmp. 145-148°. 

Methoxycarbonyl-methyl)-5-phenyl-5,6-dihydro- dibenzo b,d]phosphoririy-5-oxid (R = C6H5) 33% 5-Benzyl-6-(methoxycarbonyl-methyl)-5,6-dihydro-(dibenzo[b,d]phosphorin -5-oxid (R — CH2-C6H5) 16% ... 

Hydroxy-9,10-dihydro- (dibenzo[b d]-A.s-phosphorin)-9-oxid7 61% Schmp. 236-238 ... 

Substituted dibenzophospholes (3) on treatment with benzoyl chloride in the presence of trimethylamine, followed by hydrolysis undergo ring expansion to yield 5,6-dihydro-dibenzo[b,d]phosphorin 5-oxides (4) in high yield (D.W. Allen and A.C. Oades, J. chem. Soc., Perkin I, 1976, 2050). 

H-pyrrolo[2,l-a] isoindoles quinolines quinolizines quinuclidines with 1 hetero atom other than O or N dibenzostannols dinaphthothiophenes phospholines phosphorins stibiafluorenes thieno[4, 3, 2"-4,5,6]steroids Ihietanes thiochromans thiophenes thiopyrylium salts thioxanthylium salts with 2 0-atoms benzodioxanes benzofuro[2,3-b]benzofurans chromeno [3,4-bJ chromenes coumarinocoumarones dibenzo-p-dioxins... 

Anionic Friedei-Crafts Complements. Regiospecific Routes to Xanthen-9-ones and Dibenzo[b,e]phosphorin-10-ones... 

Phospha-Michael reactions are useful to establish a P-C bond. The addition of >P(0)H species (e.g., dialkyl phosphites and secondary phosphine oxides) at the end of electron-poor double bonds may be facilitated by bases, like NaOR, NaOH, or DBU [56]. The addition of P-heterocyclic nucleophiles was also studied. Dibenzo[c.e][l,2]oxa-phosphorine oxide (36) added easily on the double bond of methyl vinyl ketone xmder MW conditions in the absence of any solvent (Scheme 12) [57]. 

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