Joumal of Organometallic Chemistry, 465 (1994) 291-304 291 JOM 23917 Reactions of unsaturated electrophiles with tram-( PMe,) ,Pd( Ph)( NHPh) James M. Boncella and Lawrence A. Villanueva Deparbnent of Chemiwy and Center for Catalysis, University of Florida, Gainesville, FL 32611-2046 (USA) (Received January 12, 1993; in revised form May 21, 1993) Abstract The complex trap-(PMe,),Pd(PhXNHPh) (1) reacts with the unsaturated electrophiles CO*, RNCO (R = Ph, ‘Bu, 2,6-‘PrC,H,), Ph,C=CkO and maleic anhydride. The less bulky substrates, CO, and maleic anhydride, react by net insertion into the Pd-N bond, while the bulky electrophiles ‘BUNCO, (2,6-‘Pr-C,H3) NCO, and Ph,GC=O react by N-H addition. 15N labeling experiments show that the initial product of the reaction of phenylisocyanate with 1 is the Pd-N insertion product which then tautomerizes to the N-H addition product. Key words: Palladium; Unsaturated electrophiles 1. Introduction There has been a growing interest in the synthesis of late transition metal amide complexes [ll. One goal of these studies has been to define the reactivity of the M-NR, group with unsaturated organic compounds. Of particular interest is the determination of whether or not M-NR, complexes can mediate C-N bond forming reactions that are similar to the C-C bond forming reactions mediated by metal alkyl complexes. Recent interest in this chemistry has resulted in the synthesis of a variety of new metal amide complexes [2], and the emergence of the reactivity patterns of these compounds [3]. In particular, metal amide com- plexes have been shown to undergo insertion or addi- tion reactions with CO,, RNCO and CO [4]. This paper describes the synthesis of the anilide complex truns-(PMe,),Pd(PhXNHPh) (1) and its reactions with the unsaturated electrophiles CO,, RNCO, Ph,CXkO, and maleic anhydride. 2. Results 2.1. Preparation and characterization of trans- (PiWe,), Pd(Ph(NHPh) (I) The anilide complex trans-(PMe,),Pd(PhXNHPh) (1) was prepared by the reaction of tram-(PMe,),- Correspondence to: Dr. J.M. Boncella. 0022-328X/94/$7.00 SSDZ 0022-328k(93)23917-M Pd(Ph)I with KNHPh in THF at room temperature (eqn. (1)). PMe, PhiPd/-’ + KNHPh A Me,P 12 h PMe, PhiPd(--NHPh Me,P 1 Removal of the THF under reduced pressure (1) and recrystallization of the resultant brown oil from diethyl ether at 0°C affords compound 1 as yellow crystals in 53% yield. Compound 1 is air sensitive in solution and in the solid state, but is stable under an argon atmo- sphere at room temperature. It slowly decomposes when heated to > 90°C by losing phosphine and dimer- izing (the chemistry associated with dimerization and subsequent reductive elimination will be reported sep- arately). The ‘H NMR spectrum of 1 in C,D, reveals a triplet at 0.74 ppm for the protons of PMe,, a broad singlet at 1.66 ppm for the N-H proton, and three well defined peaks in the phenyl region. The 31P(1H] NMR spectrum reveals a singlet at - 16.79 ppm, consistent with the presence of trans phosphine ligands. The 0 1994 - Elsevier Sequoia. All rights reserved