ISSN:
0009-2940
Keywords:
Deprotonation
;
1,5-Homodienyl shift
;
Bicyclo[3.2.2]nona-2,6,8-trienes
;
Tricyclo[3.2.2.02,4]nona-6,8-dienes
;
Barbaralanes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Five different anions are formed when bicyclo[3.2.2]nona-2,6,8-triene (1a) is deprotonated: the 6- and 7-yl anions when using tBuLi/TMEDA, the 4,6- and 4,7-diyl dianions when using nBuLi/tBuOK, and the 4-yl anion (1-) after quenching the dianions with THF. Reaction of the anions with Me3SnCl gives the 6-, 7-, and 4-monostannylated bicyclo[3.2.2]nona-2,6,8-trienes 1b, 1c, and 1d as well as the exo-4,7-, endo-4,6-, and endo-4,7-distannylated bicyclo[3.2.2]nona-2,6,8-trienes 1e, 1f, and 1g, respectively. Reaction of 1- with Me3SiCl and Me3PbCl leads to the corresponding 4-silyl derivative 1h and its plumbyl analogue 1i. Inversely, cleavage of 1d with MeLi allows to generate 1- under particularly mild conditions. The metallation of tricyclo[3.2.2.02,4]nona-6,8-diene (3a), which was tested for an alternative route to 1-, gives two stannyl derivatives 3b and 3c which are substituted in the vinylic positions. - On heating 1d and 1i rearrange to yield 9-trimethylstannylbarbaralane (2d) and its plumbyl analogue 2i quantitatively. The reactivity decreases on passing from 1i to 1d whereas 1h does not react. Mercury and zinc derivatives of 1- are so labile that only dibarbaralylmercury (2j) and -zinc (2k) are observed by NMR spectroscopy. The title rearrangement proceeds by a 1,5-homodienyl metallatropic shift which involves an endo1-type transition structure. - The new compounds 1b - i, 2d, 2i, 3b and 3c are characterized with emphasis on the NMR data including 1H, 13C, 119Sn, 207Pb signal shifts and various heteronuclear couplings.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931260604
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