Finally, we attempted the conversion of BCB-phthalimides 3 to aminomethyl-BCBs 4. We expected this might be challenging due to the highly reactive nature of the BCB central C-C σ bond. 3A Out of the twenty BCB-phthalimides 3a-t, we were able to isolate 13 aminomethyl-BCBs 4 following treatment with hydrazine (Table ). Each compound was purified by reversephase HPLC with ammonium acetate buffer and isolated as the acetate salt. An X-ray crystal structure of 4a confirmed the ionic bond along with a bound water molecule (Table ). Table . Hydrazinolysis of BCB-phthalimides 3 to aminomethyl-BCBs 4 a We demonstrated an application of the classic Gabriel synthesis to form BCBs bearing a primary amine handle. Traditionally, the Gabriel sequence is performed with primary alkyl halides, while secondary/tertiary alkyl halides are not tolerated. Iodo-BCPs are a special kind of tertiary alkyl halide that undergo substitution accompanied by skeletal rearrangement when they are heated with a nucleophile. We expanded our scope of nucleophiles (1°, 2° amines, thiols, and sulfinates) to include phthalimide, which has important utility as an precursor. The process we describe in this paper to make aminomethyl-BCBs uses no organometallic reagents or transition metals. Moreover, the iodo-BCPs are readily synthesized from commercially-available and inexpensive acid-BCPs. Despite these advantages, our current sequence is limited by low yields of the 2 to 3 rearrangement reaction, which deserves further investigation and optimization. Currently we are working to try and improve the conversion and suppress decomposition pathways. Ultimately, we hope to be able to expand upon library compound collections by adding amine-functionalized BCB reagents with this chemistry.