Heterocyclics 9-borabicyclo nonane

On the basis of the observation that the acyloxy function of carboxylic acids is not readily reduced by 9-BBNH (9-borabicyclo[3.3.1]nonane), hydrogen evolution and formation of heterocycles like 169 was the expected outcome... 

Nuclear Magnetic Resonance Spectroscopy.—As noted above, conformational analysis of bicyclo[3.3.1]nonanes is still a topic of considerable interest. A variable-temperature n.m.r. analysis now provides the first case in which the boat-chair-chair-boat equilibrium is directly observed in the amines (17) and (18). In a related case, re-examination of the acetal (19) suggests that the preferred conformation involves a chair carbocyclic ring and a boat heterocyclic ring. This conclusion was made by n.m.r. analysis, using lanthanide shift reagents, by a study of nuclear Overhauser effects, and by measurement of relaxation times of protons. Details have been reported for other 3-azabicyclo[3.3.1]nonanes, and the non-additivity of substituent effects on chemical shifts in 9-thiabicyclo[3.3.1]non-2-enes has been analysed. Both and n.m.r. data have been reported for a series of 9-borabicyclo[3.3.1]non-anes and their pyridine complexes. 

The reactions of 9-Cl-9-borabicyclo[3.3.1]nonane (9-C1-9-BBN) or 9-MeO-9-BBN with MeSCH2Li-(TMEDA) have been investigated, leading to the isolation of the unprecedented boron—sulfur heterocycles 117 and 118 (Scheme 39) (2014OM4336). The former product 117, an inner salt formally composed of sulfonium and borate subunits, rearranges... 

B,S- and B,Se-Heterocycles and novel polymeric materials 98AG(E)3208. Olefins with 9-borabicyclo[3.3.1]nonane residues in the synthesis of borane-containing polyolefins 99JOM(581)176. 

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