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Approaches to Destabilized 7-Norbornyl Cations

Wolfgang Kirmse ; Ruhr-Universitat Bochum, Fakultat für Chemie, P.O.B. 102148, D-4630 Bochum, Germany
Sabine Schoen ; Ruhr-Universitat Bochum, Fakultat für Chemie, P.O.B. 102148, D-4630 Bochum, Germany

Sažetak

2-Oxo-7-norbornyl cations and l-eyano-7-norbornyl cations have been generated from various precursors, mostly derivatives of bicyclo[3.2.0]hep- tane. Whereas 2-bromobicyclo[3.2.0]heptan-3-one (17) solvolyzed exclusively with formation of 2-methoxybicyclo[3.2.0]heptan-3-ones (19,20), the analogous diazonium ion rearranged in part to give syn-7-methoxynorbornan-2-one (29). The epimeric 2-brosyloxybicyclo[3.2.0]heptane-2-carbonitriles (34,35) solvolyzed with predominant migration of C-7, yielding l-cyano-7-norbomyl derivatives without significant anti -*syn leakage. Similarly, the decomposition of 5-cyanobicyclo[3.2.0]heptane-2-diazonium ions (47) led to 7-hydroxynor- bornane-l-carbonitrile (38) in a stereospecific manner. Slightly lower stereoselectivity (ca 90%) was observed in solvolyses of labeled l-cyano-7-norbornyl triflate (39). While the stereochemical data conform with those of the parent system, the lack of bridge flipping (40242) points to graded destabilization of bridged and open ions.

Ključne riječi

Hrčak ID:

137116

URI

https://hrcak.srce.hr/137116

Datum izdavanja:

15.10.1992.

Posjeta: 1.070 *