A facile synthesis of the new electron-rich, sterically hindered proazaphosphatrane shown above is described herein. This proazaphosphatrane catalyzes the cyclotrimerization of a wide variety of isocyanates to isocyanurates under mild conditions with unprecedentedly fast reaction times, giving moderate to high product yields. It is also shown that this proazaphosphatrane can be recycled up to 5 times.
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http://dx.doi.org/10.1021/jo9023396 | DOI Listing |
J Org Chem
August 2010
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
A facile synthesis of the new electron-rich, sterically hindered proazaphosphatrane shown above is described herein. This proazaphosphatrane catalyzes the cyclotrimerization of a wide variety of isocyanates to isocyanurates under mild conditions with unprecedentedly fast reaction times, giving moderate to high product yields. It is also shown that this proazaphosphatrane can be recycled up to 5 times.
View Article and Find Full Text PDFJ Org Chem
September 2009
Department of Chemistry, 1275 Gilman Hall, Iowa State University, Ames, Iowa 50011, USA.
Proazaphosphatrane P(PhCH(2)NCH(2)CH(2))(3)N (1a) is an efficient catalyst for the addition of aryl trimethylsilyl alkynes to a variety of aromatic, aliphatic, and heterocyclic aldehydes in THF at room temperature. The reaction conditions are mild and employ a low catalyst loading (ca. 5 mol %).
View Article and Find Full Text PDFJ Org Chem
April 2007
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Pro-azaphosphatrane 1a [P(iBuNCH2CH2)3N] reacts with iodine under mild conditions to give [IP(iBuNCH2CH2)3N]I in excellent yield, which on subsequent reaction with ammonia followed by deprotonation with KOtBu provided HN=P(iBuNCH2CH2)3N (3a) in quantitative yield. Reaction of 3a with R'2PCl afforded sterically bulky electron-rich phosphines of the type R'2PN=P(iBuNCH2CH2)3N (4) [R'=Ph (4a), iPr (4b), tBu (4c)]. The Pd(OAc)2/4c catalyst system was particularly efficient for the coupling of arylboronic acids with aryl bromides as well as aryl chlorides to give biaryls in excellent yields.
View Article and Find Full Text PDFJ Org Chem
October 2003
Department of Chemistry, Gilman Hall, Iowa State University, Ames, Iowa 50011-3111, USA.
The new bicyclic triaminophosphine ligand P(i-BuNCH2)3CMe (3) has been synthesized in three steps from commercially available materials and its efficacy in palladium-catalyzed reactions of aryl halides with an array of amines has been demonstrated. Electron-poor, electron-neutral, and electron-rich aryl bromides, chlorides, and iodides participated in the process. The reactions encompassed aromatic amines (primary or secondary) and secondary amines (cyclic or acyclic).
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