SYNTHESIS OF CHIRAL 2-METHYL-3-ALKENOIC ESTERS<i>VIA</i>1,2-REARRANGEMENT OF ALKENYL GROUP
作者:Yutaka Honda、Aiichiro Ori、Gen-ichi Tsuchihashi
DOI:10.1246/cl.1986.13
日期:1986.1.5
Hydrolysis of optically pure 1-alkenyl-2-sulfonyloxy-1-propanone acetals afforded optically and geometrically pure title compounds via stereospecific 1,2-rearrangement of alkenyl group.
Anion-Binding Properties of a Cyclic Pseudohexapeptide Containing 1,5-Disubstituted 1,2,3-Triazole Subunits
作者:Martin R. Krause、Richard Goddard、Stefan Kubik
DOI:10.1021/jo201024r
日期:2011.9.2
cyclic peptide and the cyclic pseudopeptide are structurally closely related. Most importantly, both exhibit a converging arrangement of the NH groups, hence a good preorganization for anion binding. As a consequence, the pseudopeptide also very efficiently interacts with halide and sulfate ions, and this is the case even in competitive aqueous solvent mixtures. However, there are clear differences in the
Formation of a cyclic tetrapeptide mimic by thermal azide–alkyne 1,3-dipolar cycloaddition
作者:Martin R. Krause、Richard Goddard、Stefan Kubik
DOI:10.1039/c0cc01154a
日期:——
Cyclodimerisation of an appropriate α,Ï-difunctionalised precursor via thermal azideâalkyne 1,3-dipolar cycloaddition affords a cyclic pseudotetrapeptide whose conformation closely resembles that of a previously prepared analogue containing L-proline and 6-aminopicolinic acid subunits.
Pharmaceutically useful optically active .alpha.-arylalkanoic acids or esters, ortho esters, or amides thereof are stereoselectively prepared by contacting an aryl magnesium Grignard reagent with an optically active .alpha.-substituted acyl halide to form the optically active aryl .alpha.-substituted alkyl ketone, which is ketalized and rearranged to the desired optically active .alpha.-arylalkanoic acid or the corresponding ester, ortho ester or amide. In an alternate embodiment, the aryl .alpha.-substituted alkyl ketone is reduced to the corresponding alkanol, which is rearranged to the .alpha.-arylalkanal. The alkanal so produced is converted to the desired optically active .alpha.-arylalkanoic acid by conventional methods.
Stereoselective Halogenation in Friedel-Crafts Acylation of 1-Acetylindoline with Chiral 2-(Methanesulfonyloxy)propionyl Chlorides.
作者:Masaaki BAN、Kosuke OKAZAKI、Motoyasu OZAWA、Makio KITAZAWA、Akikazu KAKEHI、Suketaka ITO
DOI:10.1248/cpb.45.765
日期:——
The Friedel-Crafts acylation of 1-acetylindoline with (S)-2- or (R)-2-(methanesulfonyloxy)propionyl chloride, and aluminum chloride in dichloromethane at room temperature did not afford the expected (S)- or (R)-1-acetyl-5-[2-(methanesulfonyloxy)propionyl]indoline, but gave optically pure (R)- or (S)-1-acetyl-5-(2-chloropropionyl)indoline, whose stereochemistry at the asymmetric carbon was inverted during the reaction. Similar reaction of 1-acetylindoline with the same chiral acylating agents in the presence of aluminum bromide gave mainly the corresponding 2-bromopropionyl derivatives, but as stereo mixtures.