4896 Organometallics 2005, 24, 4896-4898 Insertion Reactions of Allenes Giving Vinyl Complexes Peng Xue, Jun Zhu, Herman S. Y. Hung, Ian D. Williams, Zhenyang Lin,* and Guochen Jia* Department of Chemistry and Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Received August 6, 2005 Summary: Treatment of OsHCl(PPh3)3 with allenes Scheme 1 CH2dCdCHR at room temperature in benzene produced the vinyl complexes OsCl(C(CH3)dCHR)(CH2dCdCHR)- 3 (PPh3)2, instead of η -allyl complexes as normally ob- served. DFT calculations show that the formation of the vinyl complex is favored kinetically. There has been great interest in transition-metal- catalyzed reactions of allenes.1,2 Insertion of allenes into M-R bonds represents one of the most important fundamental steps in catalytic reactions of allenes. In principle, allenes can undergo insertion reactions with LnM-R to give either transition-metal allyl complexes A or vinyl complexes B, as illustrated in eq 1. The plexes are now well documented. Although catalytic reactions involving insertion of allenes into M-R bonds to give vinyl intermediates were occasionally proposed,6 stoichiometric insertion reactions of allenes with well- defined LnM-R to give vinyl complexes cannot be found in the literature, to the best of our knowledge. In this insertion of allenes into M-R bonds to give allyl work, we wish to report the first examples of formation intermediates has been frequently invoked in the mech- of vinyl complexes from allene insertion reactions. anisms of transition-metal-catalyzed reactions of al- 7 d d lenes. In supporting the proposed mechanisms, stoichio- Treatment of OsHCl(PPh3)3 (1) with CH2 C CHC- metric insertion reactions of allenes with L M-R(M) Me3 at room temperature in benzene produced OsCl(C- n d d d Pd(II) or Pt(II),3 Rh(I),4 Ru(II);5 R ) halide, H, acyl, allyl, (CH3) CHCMe3)(CH2 C CHCMe3)(PPh3)2 (2) (Scheme vinyl, alkyl, aryl) to give transition-metal allyl com- 1). The structure of 2 has been confirmed by a single- crystal X-ray diffraction study.8 As shown in Figure 1, 2 (1) (a) Ma, S. Acc. Chem. Res. 2003, 36, 701. (b) Sydnes, L. K. Chem. complex 2 contains an η -CH2dCdCHCMe3 ligand and Rev. 2003, 103, 1133. (c) Zimmer, R.; Dinesh, C. U.; Nandanan, E.; the vinyl ligand MeCdCHCMe , which interacts with Khan, F. A. Chem. Rev. 2000, 100, 3067. 3 (2) Examples of recent experimental work: (a) Trost, B. M.; Stiles, the osmium center agostically through one of the D. T. Org. Lett. 2005, 7, 2117. (b) Ng, S. S.; Jamison, T. F. J. Am. hydrogen atoms of the R-methyl group. In agreement Chem. Soc. 2005, 127, 7320. (c) Wegner, H. A.; de Meijere, A.; Wender, 1 P. A. J. Am. Chem. Soc. 2005, 127, 6530. (d) Ma, S.; Gu, Z. J. Am. with the solid-state structure, the H NMR spectrum Chem. Soc. 2005, 127, 6182. (e) Chang, K. J.; Rayabarapu, D. K.; Yang, showed the agostic methyl proton signal at -0.84 ppm. F. Y.; Cheng, C. H. J. Am. Chem. Soc. 2005, 127, 126. (f) Shibata, T.; The chemical shift is unusually upfield for a typical CH Kadowaki, S.; Takagi, K. Organometallics 2004, 23, 4116. 3 2 (3) (a) Canovese, L.; Visentin, F.; Chessa, G.; Uguagliati, P.; Santo, attached to an sp -hybridized carbon but is close to that C.; Bandoli, G.; Maini, L. Organometallics 2003, 22, 3230. (b) Yagyu, of the methyl group with an agostic interaction in [IrPh- T.; Suzaki, Y.; Osakada, K. Organometallics 2002, 21, 2088. (c) Yagyu, d d - 9 T.; Hamada, M.; Osakada, K.; Yamamoto, T. Organometallics 2001, (C(CH CHCMe3) CHCMe3)(PMe3)3]PF6 ( 0.7 ppm). 20, 1087. (d) Canovese, L.; Visentin, F.; Chessa, G.; Uguagliati, P.; Complex 2 represents a rare example of â-agostic vinyl Bandoli, G. Organometallics 2000, 19, 1461. (e) Delis, J. G. P.; Groen, J. H.; Vrieze, K.; van Leeuwen, P. W. N. M.; Veldman, N.; Spek, A. L. Organometallics 1997, 16, 551. (f) Kacker, S.; Sen, A. J. Am. Chem. (5) (a) Xue, P.; Bi, S.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.; Jia, G. Soc. 1997, 119, 10028. (g) Groen, J. H.; Elsevier, C. J.; Vrieze, K.; Organometallics 2004, 23, 4735. (b) Sasabe, H.; Nakanishi, S.; Takata, Smeets, W. J. J.; Spek, A. L. Organometallics 1996, 15, 3445 and T. Inorg. Chem. Commun. 2003, 6, 1140. (c) Sasabe, H.; Nakanishi, references therein. (h) Hughes, R. P.; Powell, J. J. Organomet. Chem. S.; Takata, T. Inorg. Chem. Commun. 2002, 5, 177. (d) Nakanishi, S.; 1973, 60, 409 and references therein. (i) Clark, H. C.; Milne, C. R. C.; Sasabe, H.; Takata, T. Chem. Lett. 2000, 1058. (e) Hill, A. F.; Ho, C. Wong, C. S. J. Organomet. Chem. 1977, 136, 265. (j) Chisholm, M. H.; T.; Wilton-Ely, D. E. T. Chem. Commun. 1997, 2207. Clark, H. C. Inorg. Chem. 1973, 12, 991. (6) (a) Fu, C.; Ma, S. Org. Lett. 2005, 7, 1605. (b) Arredondo, V. M.; (4) (a) Chokshi, A.; Rowsell, B. D.; Trepanier, S. J.; Ferguson, M. McDonald, F. E.; Marks, T. J. Organometallics 1999, 18, 1949. (c) J.; Cowie, M. Organometallics 2004, 23, 4759. (b) Choi, J.; Osakada, Arredondo, V. M.; Tian, S.; McDonald, F. E.; Marks, T. J. J. Am. Chem. K.; Yamamoto, T. Organometallics 1998, 17, 3044. (c) Osakada, K.; Soc. 1999, 121, 3633-3639. Choi, J. C.; Yamamoto, T. J. Am. Chem. Soc. 1997, 119, 12390. (d) (7) Ferrando, G.; Caulton, K. G. Inorg. Chem. 1999, 38, 4168. Sovago, J.; Newton, M. G.; Mushina, E. A.; Ungvary, F. J. Am. Chem. (8) See the Supporting Information for experimental and spectro- Soc. 1996, 118, 9589. (e) Osakada, K.; Choi, J. C.; Koizumi, T.; scopic details of 2-6, for X-ray studies of 2 and 5, and for computational Yamaguchi, I.; Yamamoto, T. Organometallics 1995, 14, 4962 and details. references therein. (9) Yi, C. S.; Liu, N. Organometallics 1998, 17, 3158. 10.1021/om0506825 CCC: $30.25 © 2005 American Chemical Society Publication on Web 09/15/2005 Communications Organometallics, Vol. 24, No. 21, 2005 4897 Figure 2. X-ray structure of 5. Selected bond distances Figure 1. X-ray structure of 2. Selected bond distances (Å) and angles (deg): Os(1)-Cl(1), 2.4511(7); Os(1)-P(1), (Å) and angles (deg): Os(1)-Cl(1), 2.4570(6); Os(1)-P(1), 2.3801(8); Os(1)-(P2), 2.4142(8); Os(1)-C(3), 2.405(3); 2.3780(6); Os(1)-(P2), 2.3646(6); Os(1)-C(1), 2.501(2); Os(1)-C(4), 2.416(3); Os(1)-C(12), 2.078(3); Os(1)-O(11), Os(1)-C(2), 2.026(2); Os(1)-C(11), 2.122(2); Os(1)-C(12), 2.144(2); C(3)-C(4), 1.367(5); C(2)-C(3), 1.336(5); O(11)- 2.044(2); C(1)-C(2), 1.498(3); C(2)-C(3), 1.332(4); C(11)- C(10), 1.261(4); C(10)-C(11), 1.416(5); C(11)-C(12), 1.363(5); C(12), 1.428(3); C(12)-C(13), 1.321(3); C(11)-C(12)-C(13), C(12)-C(13), 1.504(4); C(2)-C(3)-C(4), 142.6(3). 142.9(2). complexes.10 â-Agostic vinyl complexes are interesting, it slowly isomerized to complex 5, in which the vinyl as they can be regarded as the resting states for the ligand is chelated to osmium though a C atom and an interconversion of allene and vinyl complexes.11 O atom. The structure of 5 has been confirmed by X-ray diffraction (Figure 2). The solution NMR data are fully The vinyl ligand MeCdCHCMe in 2 is derived from 3 consistent with the solid-state structure. insertion of CH dCdCHCMe into an Os-H bond. A 2 3 The reactions described above demonstrate that al- number of allene insertion reactions have been reported, lenes with either electron-donating or -withdrawing for example, in the reactions of allenes with complexes groups undergo insertion reactions with OsHCl(PPh ) such as [MR(sol)(L-L)]+ (M ) Pt, Pd; L ) nitrogen, or 3 3 at the less substituted CdC bond to give vinyl complexes sulfur or phosphorus donors),3 RhH(L)(PPh ) (L ) CO, 3 3 instead of η3-allyl complexes, as normally observed. To PPh ),4 RuHCl(CO)(PPh ) ,5a and RuH(NO)(PPh ) .5b In 3 3 3 3 3 understand why allyl complexes were not produced in all these reported reactions, the isolated products are the reactions of OsHCl(PPh ) , we have studied the allyl complexes. Thus, the formation of complex 2 from 3 3 formation of vinyl versus η3-allyl complexes from the the reaction of 1 with CH dCdCHCMe is interesting 2 3 model reaction of OsHCl(PH ) with H CdCdCH by and unexpected, as it represents the first example of 3 3 2 2 density functional theory calculations.8 Figure 3 shows formation of vinyl complexes from allene insertion the potential energy profiles for the two insertion reactions. pathways leading to the formation of the vinyl (PR- To see if the reactions are general, we have studied vinyl) and allyl (PR-allyl) model complexes. The the reactions of OsHCl(PPh ) with other allenes. Reac- 3 3 results indicate that the formation of the vinyl complex tion of OsHCl(PPh ) with CH dCdCHPh produced the 3 3 2 is kinetically favorable.