Low-Temperature X-ray Crystal-Structure Analysis of the Thermally Unstable Lithiated 2-Butenyl tert-Butyl Sulfide: A comparison with model ab initio MO calculations
✍ Scribed by Dieter Seebach; Thomas Maetzke; Richard K. Haynes; Michael N. Paddon-Row; Stephen S. Wong
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- German
- Weight
- 661 KB
- Volume
- 71
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Single crystals of the N,N,N',Wtetramethylethylenediamine (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 -707, compound 6 is best described as a (E)-l-(fert-butylthio)-l-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 f-Bu group and the Li-atom are located above and below this plane. The structure is discussed with respect to the reactivity of 6(a/y reactivity). The gross structure is reproduced surprisingly well by an ub initio SCF MO calculation of the model lithiopropene-I-thiol7 (HS instead of t-BUS, CH, instead of CHCH3, no solvation of Li). The prominent difference is the symmetry of the allylic moiety in the calculated structure. 1. Introduction. -Nucleophilic organometallic derivatives A of heterosubstituted allylic anions are most useful reagents in organic syntheses, because they can give M+ X A B C 0 II D E ') Part of the projected Dissertation of Th. M., ETH Zurich.