Stereoselective Synthesis of Quaternary Benzylic Carbons Using C2 Symmetric Imidazolines and Tetrahydrofuran as Electrophile
摘要:
Alkylative ring opening of tetrahydrofuran in the presence of 9-BBN triflate is studied. Dianions derived from Ct symmetric imidazolines induce excellent to modest acyclic diastereoselectivity to form quaternary benzylic centers, using the 9-BBN triflate/THF system or methyl iodide as electrophiles. The direction of the stereoinduction is consistent in both cases. Absolute configuration for the newly created stereogenic center was established by chemical correlation. Low-temperature NMR studies of the dilithiated intermediates 42 and 43 suggest the presence of N- and C-metalated compounds, where the metal-bearing benzylic carbon is sp(3) hybridized.
Histaminanaloge, 28. Mitt. 2-Aryloxyalkyl- und 2-Aminoalkylhistamine
作者:Robert Steffens、Walter Schunack
DOI:10.1002/ardp.19873200208
日期:——
Als Histaminderivate mit H1‐affinitätsvermittelnden Strukturelementen in 2‐Stellung des Imidazolrings wurden 2‐Aryloxyalkyl‐ und 2‐Aminoalkylhistamine sowie das racemische 2‐(1‐Phenylethyl)histamin dargestellt und auf Histamin‐H1‐agonistische Aktivität untersucht.
9-BBN triflate mediated stereoselective alkylation of 2-alkyl imidazolines with tetrahydrofurans
作者:Peter I. Dalko、Yves Langlois
DOI:10.1016/s0040-4039(00)79135-0
日期:1992.9
Nucleophilic attack of deprotonated imidazolines 3 or 4 on tetrahydrofuran derivatives in the presence of 9-BBN triflate can afford the corresponding alkylated products 7 with moderate to good stereoselectivities.
BREAM J. B.; PICARD C. W.; WHITE T. G., EUR. J. MED. CHEM.-CHIM. THER., 1981, 16, NO 2, 175-179