Communications
[18] Crystal data for rac-trans-11d: C33H41NO2Sn, M = 602.36,color-
less crystal 0.35 0.20 0.10 mm, a = 10.127(1), b = 11.259(1),
c = 13.926(1) , a = 96.94(1), b = 100.81(1), g = 102.87(1)8, V=
[1] For reviews,see: a) D. Hoppe,T. Hense, Angew. Chem. 1997,
109,2376; Angew. Chem. Int. Ed. Engl. 1997, 36,2282; b) H.
Ahlbrecht,U. Beyer, Synthesis 1999,365; c) D. Hoppe,F. Marr,
M. Brüggemann, Top. Organomet. Chem. 2003, 6,61; d) P. Beak,
T. A. Johnson,D. D. Kim,S. H. Lim, Top. Organomet. Chem.
2003, 6,134; e) D. Hoppe,G. Christoph in The Chemistry of
Organolithium Compounds (Eds.: Z. Rappoport,I. Marek),
Wiley,Chichester, 2004,p. 1055.
1498.4(2) 3, 1calcd = 1.335 gcmÀ3
,
m = 0.881 mmÀ1,empirical
absorption correction (0.748 ꢀ Tꢀ 0.917), Z = 2,triclinic,space
¯
group P1 (No. 2), l = 0.71073 , T= 198 K, w and f scans,13806
reflections collected (Æ h, Æ k, Æ l),[(sin q)/l] = 0.67 À1,7160
independent (Rint = 0.032) and 6493 observed reflections [I ꢁ
2s(I)],340 refined parameters, R = 0.027, wR2 = 0.066,max.
residual electron density 0.73 (À0.75) eÀ3,hydrogen atoms
calculated and refined as riding atoms.
[2] a) D. Hoppe,O. Zschage, Angew. Chem. 1989, 101,67; Angew.
Chem. Int. Ed. Engl. 1989, 28,69; b) O. Zschage,D. Hoppe,
Tetrahedron 1992, 48,5657; c) D. Hoppe,M. Özlügedik,J.
Kristensen,B. Wibbeling,R. Fröhlich, Eur. J. Org. Chem. 2002,
414.
[3] a) M. Seppi,R. Kalkofen,J. Reupohl,R. Fröhlich,D. Hoppe,
Angew. Chem. 2004, 116,1447; Angew. Chem. Int. Ed. 2004, 43,
1423; b) J. Reuber,R. Fröhlich,D. Hoppe, Org. Lett. 2004, 6,
783; c) R. Bou Chedid,R. Fröhlich,D. Hoppe, Org. Lett. 2006, 8,
3061.
[4] D. Hoppe,T. Krämer, Angew. Chem. 1986, 98,171; Angew.
Chem. Int. Ed. Engl. 1986, 25,160.
[5] a) D. Hoppe,R. Hanko,A. Brönneke, Angew. Chem. 1980, 92,
637; Angew. Chem. Int. Ed. Engl. 1980, 19,625; b) D. Hoppe,R.
Hanko,A. Brönneke,F. Lichtenberg, Angew. Chem. 1981, 93,
1106; Angew. Chem. Int. Ed. Engl. 1981, 20,1024.
[19] Data sets were collected with Nonius KappaCCD diffractom-
eters,(Mo radiation,rotating anode). Programs used: for data
collection,COLLECT (Nonius B. V., 1998); for data reduction,
Denzo-SMN (Z. Otwinowski,W. Minor, Methods Enzymol.
1997, 276,307); for absorption correction SORTAV(R. H.
Blessing, Acta Crystallogr. Sect. A 1995, 51,33,R. H. Blessing,
J. Appl. Crystallogr. 1997, 30,421),and Denzo (Z. Otwinowski,
D. Borek,W. Majewski,W. Minor, Acta Crystallogr. Sect. A 2003,
59,228); for structure solution,SHELXS-97 (G. M. Sheldrick,
Acta Crystallogr. Sect. A 1990, 46,467); for structure refinement,
SHELXL-97 (G. M. Sheldrick,Universität Göttingen, 1997); for
graphics,SCHAKAL (E. Keller,Universität Freiburg, 1997).
CCDC-616268–616270 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
[6] The starting material trans-1 was re-isolated.
[7] E. J. Corey,R. A. Sneen, J. Am. Chem. Soc. 1956, 78,6269.
[8] For the proposed TSs of ester enolization,see: R. E. Ireland,
R. H. Mueller,A. K. Willard, J. Am. Chem. Soc. 1976, 98,2868.
[9] S. M. Behnam,S. E. Behnam,K. Ando,N. S. Green,K. N. Houk,
J. Org. Chem. 2000, 65,8970.
[10] P. Beak,W. K. Lee, J. Org. Chem. 1990, 55,2578; see also: N. G.
Rodan,K. N. Houk,P. Beak,W. J. Zajdel,J. Chandrasekhar,
P. v. R. Schleyer, J. Org. Chem. 1981, 46,4108.
[20] Crystal data for trans-8e: C17H29NO2, M = 279.41,colorless
crystal 0.45 0.30 0.30 mm, a = 11.016(1), b = 11.932(1), c =
13.227(1) ,
V= 1738.6(3) 3,
1calcd = 1.067 gcmÀ3
,
m =
0.536 mmÀ1,empirical absorption correction (0.795 ꢀ Tꢀ
0.856), Z = 4,orthorhombic,space group P212121 (No. 19), l =
1.54178 , T= 223 K, w and f scans,7631 reflections collected
(Æ h, Æ k, Æ l),[(sin q)/l] = 0.60 À1,2943 independent ( Rint
=
[11] For a recent review,see: M. C. Whisler,S. MacNeil,V. Snieckus,
P. Beak, Angew. Chem. 2004, 116,2256; Angew. Chem. Int. Ed.
2004, 43,2206.
0.030) and 2814 observed reflections [I ꢁ 2s(I)],188 refined
parameters, R = 0.044, wR2 = 0.121,Flack parameter 0.1(3),
max. residual electron density 0.18 (À0.13) eÀ3,hydrogen
atoms calculated and refined as riding atoms.
[12] P. Beak,B. Lee, J. Org. Chem. 1989, 54,458.
[13] Conditions A–D were tested to optimize the yield of the
reaction,but the results were in principle identical.
[14] The use of sBuLi/diamine at À788C led to rapid (1 h) decom-
position of the starting materials 8 with loss of the carbamoyloxy
group. With nBuLi/diamine,no reaction was observed after a
short time (TLC,GC,MS),but decomposition arose with longer
reaction times.
[15] The reactions were performed with diastereomerically pure
carbamates with the exception of rac-trans-8d and rac-cis-8d,
which were found to be inseparable by flash chromatography,
HPLC,or fractional distillation. However,on deprotonation,the
minor diastereomer rac-cis-8d decomposed,and thus the
diastereomerically pure allylstannane rac-trans-10d could be
obtained.
[21] a) S. Grimme, J. Comput. Chem. 2004, 25,1463; b) J. P. Perdew,
K. Burke,M. Enzerhof, Phys. Rev. Lett. 1996, 77,385; c) A.
Schäfer,C. Huber,R. Ahlrichs, J. Chem. Phys. 1994, 100,5829;
for the importance of intramolecular van der Waals interactions
in organic reactions,see: d) S. Grimme,C. Dietrich,M. Korth,
Angew. Chem. 2006, 118,641; Angew. Chem. Int. Ed. 2006, 45,
625; e) S. Grimme, Angew. Chem. 2006, 118,4571; Angew. Chem.
Int. Ed. 2006, 45,4460.
[22] R. Ahlrichs,M. Bär,M. Häser,H. Horn,C. Kölmel, Chem. Phys.
Lett. 1989, 162,165; Turbomole (Version 5.6): R. Ahlrichs et al.,
[23] For transition states calculated for the deprotonation of N-Boc-
pyrrolidine and N-Boc-piperidine mediated by (À)-sparteine,
see: K. B. Wiberg,W. F. Bailey, Angew. Chem. 2000, 112,2211;
Angew. Chem. Int. Ed. 2000, 39,2127; K. B. Wiberg,W. F. Bailey,
J. Am. Chem. Soc. 2001, 123,8231; W. F. Bailey,P. Beak,S. T.
Kerrick,S. Ma,K. B. Wiberg, J. Am. Chem. Soc. 2002, 124,1889.
[24] For ethyl carbamate,the calculated (B3LYP/6-31G*) activation
barrier for the deprotonation with iPrLi/(À)-sparteine is
14.35 kcalmolÀ1; for allylic (1-cyclohexenyl)methyl carbamate,
the Ea is 10.78 kcalmolÀ1. See: E.-U. Würthwein,D. Hoppe, J.
Org. Chem. 2005, 70,4443.
[16] a) O. Zschage,J.-R. Schwark,T. Krämer,D. Hoppe, Tetrahedron
1992, 48,8377; b) H. Paulsen,C. Graeve,D. Hoppe,
1996,141.
Synthesis
[17] Crystal data for cis-11c: C35H43NO2Sn, M = 628.39,colorless
crystal 0.30 0.25 0.15 mm, a = 11.832(1), b = 11.953(1), c =
22.935(1) ,
V= 3243.6(4) 3,
1calcd = 1.287 gcmÀ3
,
m =
0.817 mmÀ1,empirical absorption correction (0.792 ꢀ Tꢀ
0.887), Z = 4,orthorhombic,space group P212121 (No. 19), l =
0.71073 , T= 198 K, w and f scans,17411 reflections collected
[25] For examples of organolithium complexes with monodentate
TMEDA,see: D. B. Collum, Acc. Chem. Res. 1992, 25,448,and
references therein.
(Æ h, Æ k, Æ l),[(sin q)/l] = 0.66 À1,7495 independent ( Rint
=
0.039) and 6327 observed reflections [I ꢁ 2s(I)],358 refined
parameters, R = 0.038, wR2 = 0.087,Flack parameter À0.04(2),
max. residual electron density 0.61 (À0.93) eÀ3,hydrogen
atoms calculated and refined as riding atoms.
=
[26] F is defined as the absolute value of the dihedral angle C3 C2-
C1-H.
1648
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2007, 46, 1645 –1649