(4S,8S)-4,8-bis(diphenylmethyl)-1,5,7-triazabicyclo[4,4,0]dec-5-ene; a hindered, chiral, bicyclic guanidine base with effective C 2-symmetry
作者:Peter H. Boyle、Anthony P. Davis、Kevin J. Dempsey、Gladys D. Hosken
DOI:10.1039/c39940001875
日期:——
The title compound 5 is prepared from L-methionine and investigated by computational, NMR spectroscopic and other techniques; the results indicate that the N/NH groups of 5 and its conjugate acid occupy hindered, chiral environments due to the disposition of the bulky diphenylmethyl substituents.
Synthesis of (S)-2-Amino-1,1-diphenylbutan-4-ol; conversion of an α-amino acid into an α-(diphenylmethyl) amine without loss of optical purity
作者:Peter H. Boyle、Anthony P. Davis、Kevin J. Dempsey、Gladys D. Hosken
DOI:10.1016/0957-4166(95)00373-w
日期:1995.11
The title amino-alcohol 4 is an intermediate for the preparation of chiral bicyclic amidines and guanidines, and also for polyamines with potential as ligands in enantioselective catalysis. It has been synthesized from (S)-methionine 1 via (S)-homoserine lactone 2 and amino-diol 3. Hydrogenolysis of the doubly benzylic hydroxyl group in 3 proved non-trivial, but was eventually achieved through the application of catalytic transfer methodology to the bis-acetyl derivative 14.
Synthesis of Chiral Bicyclic Guanidinium Salts using Di(imidazole-1-yl)methanimine
bicyclic guanidinium salts is presented. This work represents the first systematic investigation of an approach toward the challenging target molecules via a key guanylation step employing di(imidazole-1-yl)methanimine (6) followed by a two-fold cyclization, which resulted in guanidinium salts 8 and 10. Factors governing the regioselectivity of the final cyclization step are discussed based on further