ChemComm
Communication
3 (a) K. Griesbaum, Angew. Chem., Int. Ed., 1970, 9, 273; (b) L. Benati,
L. Capella, P. C. Montevecchi and P. Spagnolo, J. Chem. Soc., Perkin
Trans. 1, 1995, 1035; (c) M. L. Conte, S. Pacifico, A. Chambery,
A. Marra and A. Dondoni, J. Org. Chem., 2010, 75, 4644.
4 (a) V. N. Ipatieff, H. Pines and B. S. Friedman, J. Am. Chem. Soc.,
1938, 60, 2731; (b) F. Kipnis and J. Ornfelt, J. Am. Chem. Soc., 1951,
73, 822; (c) F. Wolf and H. Finke, Z. Chem., 1972, 12, 180; (d) C. G.
Screttas and M. Micha-Screttas, J. Org. Chem., 1979, 44, 713;
(e) S. Kanagasabapathy, A. Sudalai and B. C. Benicewicz, Tetrahedron
Lett., 2001, 42, 3791.
5 (a) W. E. Truce, J. A. Simms and M. M. Boudakian, J. Am. Chem. Soc.,
1956, 78, 695; (b) D. H. Wadsworth and M. R. Detty, J. Org. Chem.,
1980, 45, 4611; (c) M. S. Waters, J. A. Cowen, J. C. McWilliams,
P. E. Maligres and D. Askin, Tetrahedron Lett., 2000, 41, 141;
(d) A. Kondoh, K. Takami, H. Yorimitsu and K. Oshima, J. Org.
Chem., 2005, 70, 6468; (e) A. H. Yu, R. H. Qiu, N. Y. Tan, L. F. Peng
and X. H. Xu, Chin. Chem. Lett., 2011, 22, 687.
Scheme 1 Proposed mechanism of trityl catalysed hydrothiolation of
6 (a) M. Wathier and J. A. Love, Eur. J. Inorg. Chem., 2016, DOI:
10.1002/ejic.201501272; (b) V. Ritleng, M. Henrion and M. J.
Chetcuti, ACS Catal., 2016, 6, 890–906; (c) I. S. R. Karmel, R. J.
Batrice and M. S. Eisen, Inorganics, 2015, 3, 392–428; (d) F. Lazreg
and C. S. J. Cazin, N-Heterocycl. Carbenes, 2014, 199–242; (e) E. Genin
and V. Michelet, The Chemistry of Organogold Compounds, 2014, Pt.
2, 901–960; ( f ) A. Dondoni and A. Marra, Eur. J. Org. Chem., 2014,
3955–3969; (g) J. M. Schomaker and R. D. Grigg, Synlett, 2013,
401–407; (h) A. Ogawa, Top. Organomet. Chem., 2013, 43, 325–360;
(i) A. B. Lowe and J. W. Chan, Funct. Polym. Post-Polym. Modif., 2013,
87–118; ( j) R. Castarlenas, A. Di Giuseppe, J. J. Perez-Torrente and
L. A. Oro, Angew. Chem., Int. Ed., 2013, 52, 211–222; (k) V. P.
Ananikov and I. P. Beletskaya, Organometallics, 2012, 31,
1595–1604; (l) C. J. Weiss and T. J. Marks, Dalton Trans., 2010, 39,
6576–6588; (m) A. S. K. Hashmi and M. Buehrle, Aldrichimica Acta,
2010, 43, 27–33; (n) M. S. Eisen, Top. Organomet. Chem., 2010, 31,
157–184; (o) R. A. Stockman, Annu. Rep. Prog. Chem., Sect. B: Org.
Chem., 2007, 103, 107–124; (p) I. P. Beletskaya and V. P. Ananikov,
Eur. J. Org. Chem., 2007, 3431–3444.
1,1-diphenylethylene.
olefin affording a transient carbocation. This view is supported
by the observation of a weak interaction of benzylthiol with the
cation of 3 by NMR spectroscopy (see ESI†). This carbocation is
more sterically accessible prompting thiolate transfer, thus
affording the Markovnikov hydrothiolation product and regenera-
tion the carbocation catalyst (Scheme 1). This mechanism is con-
sistent with the lack of reactivity of primary and 1,2-disubstituted
alkenes where the generation of primary or secondary carbocations
presents a significant thermodynamic barrier. The proposed
mechanism is distinct from known routes6j involving thiol activation
where reactions are triggered by formation of free radicals, deproto-
nation by a base or by oxidative addition of SH to a metal center.
Herein, we have demonstrated that the air- and moisture-
stable trityl cation, [(MeOC6H4)CPh2][BF4] 3 is a potent catalyst
for the hydrothiolation of alkenes. These reactions proceed
under mild conditions without the use of dried or degassed solvents
or reagents. The further application of such C-based Lewis acids in
catalysis continues to be the subject of interest in on-going efforts.
The results of these studies will be reported in due course.
7 Transition-Metal-Catalyzed S–H and Se–H Bonds Addition to Unsaturated
Molecules, ed. V. P. Ananikov and M. Tanaka, Springer, New York,
2011.
8 T. Tamai and A. Ogawa, J. Org. Chem., 2014, 79, 5028.
9 (a) T. Mukaiyama, T. Izawa, K. Saigo and H. Takai, Chem. Lett., 1973,
355; (b) M. Belley and R. Zamboni, J. Org. Chem., 1989, 54, 1230.
10 K. Kucinski, P. Pawluc and G. Hreczycho, Adv. Synth. Catal., 2015,
357, 3936–3942.
˜
11 M. Weiwer, L. Coulombel and E. Dunach, Chem. Commun., 2006,
332–334.
12 R. Kumar, Saima, A. Shard, N. H. Andhare, Richa and A. K. Sinha,
Angew. Chem., Int. Ed., 2015, 54, 828–832.
´
13 M. Perez, T. Mahdi, L. J. Hounjet and D. W. Stephan, Chem.
Notes and references
Commun., 2015, 51, 11301–11304.
1 (a) Organosulfur Chemistry II, ed. P. C. B. Page, Springer, Berlin, 1991; 14 C. Huo, Y. Wang, Y. Yuan, F. Chen and J. Tang, Chem. Commun.,
(b) Organosulfur Chemistry I, ed. P. C. B. Page, Springer, Berlin, 1991.
2 T. Posner, Ber. Dtsch. Chem. Ges. B, 1905, 38, 646.
2016, 52, 7233–7236.
15 M. Horn and H. Mayr, Chem. – Eur. J., 2010, 16, 7469–7477.
This journal is ©The Royal Society of Chemistry 2016
Chem. Commun.