title: Synthesis of extended polyphosphacumulenes.
abstract: Addition of two equivalents of (Me(3)Si)(2)CLiCl to the C-[(diphenyl) (diisopropylamino)phosphonio]-P-(diisopropylamino)phosphaalkene 2 affords the 1sigma(4),3sigma(3)-diphosphabuta-1,2,3-triene E1 in 55 % yield. Derivative E1 was fully characterized, including a single-crystal X-ray diffraction study. Alkylation of E1 with methyl trifluoromethanesulfonate gives rise to the first C-phosphonio-bis(methylene)phosphorane 5, which was isolated in 84 % yield. Because the second carbon center is also nucleophilic, cumulene E1 reacts as a "pincer" with BF(3)OEt(2), leading to the formation of a novel four-membered PCBC heterocycle 6 with a betaine-like structure. Addition of three equivalents of P-[diphenyl(diisopropylamino)]methylene phosphorane to (diisopropylamino)dichlorophosphane, followed by addition of one equivalent of CCl(4), and subsequent deprotonation with lithium hexamethyldisilazide gave rise to 1sigma(4),3sigma(3),5sigma(4)-triphosphapenta-1,2,3,4-tetraene F1, which was isolated in 62 % yield.
authors.affiliation: UCR-CNRS Joint Research Chemistry Laboratory (UMI 2957), Department of Chemistry, University of California, Riverside, CA 92521-0403, USA.
authors.forename: David
authors.initials: D
authors.lastname: Martin
authors.forename: Fook S
authors.initials: FS
authors.lastname: Tham
authors.forename: Antoine
authors.initials: A
authors.lastname: Baceiredo
authors.forename: Guy
authors.initials: G
authors.lastname: Bertrand