Journal of the American Chemical Society
Communication
R.; Carson, M. W.; Ma, Y. L.; Dodge, J. A. In Vitamin D; Feldman, D.,
Pike, J. W., Adams, J. S., Eds.; Elsevier: London, 2011; pp 1497−1508.
(2) For examples and leading references, see: (a) Woodmansee, D. H.;
Pfaltz, A. Chem. Commun. 2011, 47, 7912. (b) Tolstoy, P.; Engman, M.;
Paptchikhine, A.; Bergquist, J.; Church, T. L.; Leung, A. W.-M.;
Andersson, P. G. J. Am. Chem. Soc. 2009, 131, 8855; this reference
includes a discussion of other approaches to the synthesis of 1,1-
diarylalkanes.
(3) For example, see: Paquin, J.−F.; Defieber, C.; Stephenson, C. R. J.;
Carreira, E. M. J. Am. Chem. Soc. 2005, 127, 10850.
(4) For recent reports and leading references, see: (a) Maity, P.;
Shacklady-McAtee, D. M.; Yap, G. P. A.; Sirianni, E. R.; Watson, M. P. J.
Am. Chem. Soc. 2013, 135, 280. (b) Zhou, Q.; Srinivas, H. D.; Dasgupta,
S.; Watson, M. P. J. Am. Chem. Soc. 2013, 135, 3307. (c) Harris, M. R.;
Hanna, L. E.; Greene, M. A.; Moore, C. E.; Jarvo, E. R. J. Am. Chem. Soc.
2013, 135, 3303 (doubly benzylic electrophiles).
(5) For an example of an umpolung process that employs an
enantioenriched benzylic nucleophile, see: Imao, D.; Glasspoole, B. W.;
Laberge, V. S.; Crudden, C. M. J. Am. Chem. Soc. 2009, 131, 5024.
(6) For recent examples and leading references, see: (a) Binder, J. T.;
Cordier, C. J.; Fu, G. C. J. Am. Chem. Soc. 2012, 134, 17003. (b) Choi, J.;
Fu, G. C. J. Am. Chem. Soc. 2012, 134, 9102. (c) Wilsily, A.; Tramutola,
F.; Owston, N. A.; Fu, G. C. J. Am. Chem. Soc. 2012, 134, 5794.
(d) Oelke, A. J.; Sun, J.; Fu, G. C. J. Am. Chem. Soc. 2012, 134, 2966.
(7) For a recent application in a total synthesis of a natural product
(carolacton), see: Schmidt, T.; Kirschning, A. Angew. Chem., Int. Ed.
2012, 51, 1063.
(8) Arp, F. O.; Fu, G. C. J. Am. Chem. Soc. 2005, 127, 10482.
(9) Under conditions described in ref 6a, the cross-coupling of a
benzylic halide with an arylzinc reagent proceeded in poor yield and
poor ee. See also footnote 6c in ref 8.
(10) For a previous example of a nickel-catalyzed cross-coupling of an
alkyl sulfonate, see: Terao, J.; Watanabe, H.; Ikumi, A.; Kuniyasu, H.;
Kambe, N. J. Am. Chem. Soc. 2002, 124, 4222.
(11) For leading references, see: (a) Kochi, J. K.; Hammond, G. S. J.
Am. Chem. Soc. 1953, 75, 3443. (b) Hammond, G. S.; Peloquin, J.; Fang,
F. T.; Kochi, J. K. J. Am. Chem. Soc. 1960, 82, 443. (c) Coates, R. M.;
Chen, J. P. Tetrahedron Lett. 1969, 10, 2705.
(12) For example, see: (a) Smith, S. W.; Fu, G. C. J. Am. Chem. Soc.
2008, 130, 12645. (b) Lundin, P. M.; Esquivias, J.; Fu, G. C. Angew.
Chem., Int. Ed. 2009, 48, 154. (c) Refs 6b and 6d.
(13) In a preliminary experiment under our standard conditions, a
highly hindered electrophile (R = isopropyl) was not a suitable cross-
coupling partner.
(14) Benzylic bromides and iodides wherein the aromatic group is
electron-rich can be highly reactive and therefore difficult to isolate.
(15) In preliminary experiments under our standard conditions, an
electrophile in which the aromatic group was hindered (o-tolyl) or very
electron-poor (cyano- or ester-substituted) was not a suitable cross-
coupling partner.
(16) For leading references to nickel-catalyzed cross-coupling
reactions of aryl electrophiles, including processes that involve C−O
bond cleavage: Yamaguchi, J.; Muto, K.; Itami, K. Eur. J. Org. Chem.
2013, 19.
(17) For a suggestion of a tosylate-to-iodide substitution in an iron-
catalyzed cross-coupling reaction: Ito, S.; Fujiwara, Y.-i.; Nakamura, E.;
Nakamura, M. Org. Lett. 2009, 11, 4306.
(18) (a) The improved yield for the cross-coupling of the benzylic
iodide in the presence of LiI (eq 2) may be due to an increase in the
dielectric constant of the reaction medium or to nucleophilic activation
of the organozinc reagent. (b) Under otherwise identical conditions, a
benzylic bromide cross-coupled in comparable yield but slightly lower
ee, whereas a benzylic chloride was not a suitable electrophile. (c) In
preliminary studies, ZnPh2 was not an effective cross-coupling partner.
(19) Quallich, G. J. Chirality 2005, 17, S120.
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dx.doi.org/10.1021/ja408561b | J. Am. Chem. Soc. XXXX, XXX, XXX−XXX