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Reactions of 1,1- and 1,2-bis-boranes with a protic diamine and hydrazine
Jason Yeung1, Amir Yeganeh-Salman1, Linkun Miao1
1Department of Chemistry, University of Toronto, 80 St George St, Toronto, ON, Canada M5S3H6. dstephan@chem.utoronto.ca.
Abstract:
The reactions of 1,1- and 1,2-bis-boranes, PhCH2CH(B(C6F5)2)21 and Me3SiCH(B(C6F5)2)CH2B(C6F5)22, with o-phenylenediamine and hydrazine are reported. The coordination of o-phenylenediamine gives the expected adducts, PhCH2CH(B(C6F5)2(H2N))2C6H44 and Me3SiCH(B(C6F5)2)CH2B(C6F5)2((H2N)2C6H4) 6. Under thermal duress, 4 undergoes retrohydroboration, resulting in the reaction of the diamine with HB(C6F5)2 to give (C6F5)2B(NH)(NH2)C6H45. In contrast, 6 undergoes protolytic loss of C6F5H, affording Me3SiCH(B(C6F5)2)CH2(B(C6F5)(NH2)(NH)C6H4) 7. In a related fashion, the bis-boranes react with hydrazine. In the case of bis-borane 1, the isolated adduct PhCH2CH(B(C6F5)2(NH2))2·THF 8 can be deprotonated to give species 9. In contrast, the reaction of 2 proceeds with rapid protonolysis, leading to the formation of Me3SiCH(B(C6F5)2)CHB(C6F5)(N2H3)·THF 10. This study illustrates both the reaction pathways accessible from the adducts of bis-boranes and the impact of coordination to boron on the acidity of NH groups.
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