TY - JOUR
T1 - Low‐Temperature X‐ray Crystal‐Structure Analysis of the Thermally Unstable Lithiated 2‐Butenyl tert‐Butyl Sulfide
T2 - A comparison with model ab initio MO calculations
AU - Seebach, Dieter
AU - Maetzke, Thomas
AU - Haynes, Richard K.
AU - Paddon‐Row, Michael N.
AU - Wong, Stephen S.
PY - 1988/3/16
Y1 - 1988/3/16
N2 - Single crystals of the N,N,N′,N′‐tetramethylethylenediamine (TMEDA) complex 6 of the title compound have been isolated. Compound 6 decomposes in the crystalline state above −20°. From the bond lengths and angles obtained by X‐ray crystal‐structure analysis (data collected at −70°), compound 6 is best described as a (E)‐1‐(tert‐butylthio)‐1‐lithio‐2‐butene with the double bond acting as an additional ligand on lithium (unsymmetrical allylic group). The S‐atom is in a cisoid arrangement in a common plane with the four C‐atoms of the butenyl system. The t‐Bu group and the Li‐atom are located above and below this plane. The structure is discussed with respect to the reactivity of 6 (α/γ reactivity). The gross structure is reproduced surprisingly well by an ab initio SCF MO calculation of the model lithiopropene‐1‐thiol 7(HS instead of t‐BuS, CH2 instead of CHCH3, no solvation of Li). The prominent difference is the symmetry of the allyllic moiety in the calculated structure.
AB - Single crystals of the N,N,N′,N′‐tetramethylethylenediamine (TMEDA) complex 6 of the title compound have been isolated. Compound 6 decomposes in the crystalline state above −20°. From the bond lengths and angles obtained by X‐ray crystal‐structure analysis (data collected at −70°), compound 6 is best described as a (E)‐1‐(tert‐butylthio)‐1‐lithio‐2‐butene with the double bond acting as an additional ligand on lithium (unsymmetrical allylic group). The S‐atom is in a cisoid arrangement in a common plane with the four C‐atoms of the butenyl system. The t‐Bu group and the Li‐atom are located above and below this plane. The structure is discussed with respect to the reactivity of 6 (α/γ reactivity). The gross structure is reproduced surprisingly well by an ab initio SCF MO calculation of the model lithiopropene‐1‐thiol 7(HS instead of t‐BuS, CH2 instead of CHCH3, no solvation of Li). The prominent difference is the symmetry of the allyllic moiety in the calculated structure.
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U2 - 10.1002/hlca.19880710202
DO - 10.1002/hlca.19880710202
M3 - Article
AN - SCOPUS:84986357092
SN - 0018-019X
VL - 71
SP - 299
EP - 311
JO - Helvetica Chimica Acta
JF - Helvetica Chimica Acta
IS - 2
ER -