Oxazolophanes as masked cyclopeptide alkaloid equivalents: cyclic peptide chemistry without peptide couplings

A N,N′-dioxide/Mg(OTf)2 complex catalyzed enantioselective α-addition of isocyanides to alkylidene malonates

“…The product 3ae could be efficiently converted into a useful 1,3-diol 5 through reduction with LiAlH 4 (90% yield, 95% ee). In addition, 5-aminooxazole 3ae was readily hydrolyzed in the presence of trifluoroacetic acid, 18 and dipeptide 6 could be obtained in 99% yield with the enantioselectivity maintained (1.8 : 1 d.r., 99% ee). These derivatives are important structural motifs for the synthesis of many biologically active compounds.…”

Synthesis of S‐Adenosyl‐L‐Methionine Analogs with Extended Transferable Groups for Methyltransferase‐Directed Labeling of DNA and RNA

“…Synthesis of nosylates could be achieved by reaction of a starting alcohol with nosyl chloride in the presence of pyridine (Lipshutz et al, 1990), or using sodium hydroxide as a general base (Lukinavičius et al, 2007), which in our hands proved either very slow, or not well reproducible, respectively. To achieve fast deprotonation of the alcohol and minimize hydrolysis of nosyl chloride we opted for a strong non-nucleophilic base – potassium tert -butoxide (Lukinavičius et al, 2013).…”

Total Synthesis of Paliurine F

“…The synthesis of sanjoinine G1 and the mauritines by Zhu and co‐workers incorporated an intramolecular S N Ar reaction as the macrocyclization protocol 5. Examination of these syntheses, along with the synthetic approaches to these alkaloids,6–8 reveals that the moderately complex chemical structure of these natural products is a challenging target. Primary synthetic challenges that must be overcome are: a) the formation of the alkyl aryl ether, b) the enamide formation, and c) the macrocyclization.…”