5-Carboxy-2-azabicyclo[2.1.1]hexanes as Precursors of 5-Halo, Amino, Phenyl, and 2-Methoxycarbonylethyl Methanopyrrolidines
摘要:
[GRAPHICS]Novel 5-X-substituted-2-azabicyclo[2.1.1]hexanes (X = 5-syn-Cl, -Br, -I, -Ph, -NHCOOR (R = Me, Bn, t-Bu), -CH2CH2COOMe and X = 5-anti-Br, -I, -Ph) were synthesized from the X = 5-syn-carboxy derivative. New 5-anti-X-2-azabicyclo[2.1.1]hexanes, X = NECOOR (R = Me, Bn), were prepared stereoselectively from the X = 5-anti-carboxy substrate.
In this study we successfully transferred a useful photochemical reactionfrom the UV to the visible region of the spectrum. Use of a commercially available iridium complex facilitated triplet state intramolecular [2 + 2] photocycloaddition under irradiation with the now readily available, compact and convenient blue light sources, therefore avoiding the need for direct UV irradiation. Under these
Oligomers of a 5-Carboxy-methanopyrrolidine β-Amino Acid. A Search for Order
作者:Grant R. Krow、Nian Liu、Matthew Sender、Guoliang Lin、Ryan Centafont、Philip E. Sonnet、Charles DeBrosse、Charles W. Ross、Patrick J. Carroll、Matthew D. Shoulders、Ronald T. Raines
DOI:10.1021/ol1022917
日期:2010.12.3
CD spectra for homooligomers (n = 4, 6, 8) of (1S,4R,5R)-5-syn-carboxy-2-azabicyclo[2.1.1]hexane (MPCA), a methano-bridged pyrrolidine beta-carboxylic acid, suggest an ordered secondary structure. Even in the absence of internal hydrogen bonding, solution NMR, X-ray, and in silico analyses of the tetramer are indicative of conformations with trans-amides and C-5-amide-carbonyls oriented toward the C-4 bridgehead This highly constrained beta-amino acid could prove useful in the ongoing development of well-defined foldamers.