For an improved synthesis of the recently described expanded octamethoxycubane with a central C56 core, formally obtained by inserting buta-1,3-diynediyl moieties into all C(sp3)-C(sp3) bonds of octamethoxycubane, the preparation of the optically pure methyl ether of a differentially silyl-protected trispropargylic alcohol was required. The key step of the preparation involved a diastereoselect...

A highly convergent, enantioselective total synthesis of the potent antitumor agent apoptolidin A has been completed. The key transformations include highly selective glycosylations to attach the C27 disaccharide and the C9 6'-deoxy-l-glucose, a cross-metathesis to incorporate the C1-C10 trienoate unit, and a Yamaguchi macrolactonization to complete the macrocycle. Twelve stereocenters in the p...

[reaction: see text] Very practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein-Ponndorf-Verley (MPV) reduction of protected alpha-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity wa...

Initially, lasubin II was synthesized diastereoselectively in racemic form [3]. Asymmetric syntheses of lasubin II were achieved based on stereoselective transformations of enantiomerically pure substrates [4] or, for example, via a diastereoselective aza-Diels-Alder reaction using a resolved chiral arylaldehyde tricarbonylchromium complex [5]. Recently, an enantioselectively catalyzed aza-Diel...

An efficient synthesis of novel planar chiral ferrocene-based amido-phosphine ligands was accomplished via highly diastereoselective ortho-lithiation and subsequent in situ trapping with chlorodiphenylphosphine. The palladium complexes of mono-phosphino ferrocenecarboxamide, bis-phosphino ferrocenedicarboxamide ligands, and analogues with a ferrocenophane framework were applied in the allylic a...

A single-step amino acid-catalyzed diastereoselective three-component synthesis of optically pure highly functionalized spiro[5,5]undecane-1,5,9-triones preferentially over the four stereoisomers was accomplished in very good yields with >99% ee/de. Preliminary cell culture-based in vivo screening on these molecules revealed that cis-1aca and cis-1jca are better lead compounds for HIV-1 treatme...

Fifteen novel β-lactams bearing the N-ethyl tert-butyl carbamate group 5a-o and fifteen N-(2-aminoethyl) β-lactams 6a-o were synthesized by the ketene-imine [2+2] cycloaddition reaction (Staudinger ). The cycloaddition reaction was found to be totally diastereoselective leading exclusively to the formation of the cis-β-lactam derivatives. These newly synthesized β-lactams were evaluated for the...

The divergent reactivity of D-A cyclopropane, under PTC conditions, is herein reported. Thus, a ring-opening or decyanation reaction can be achieved by reacting 2-arylcyclopropane-1,1-dicarbonitriles 1 with thioacetic acid in different conditions. use solid Cs2CO3 leads unexpectedly to the synthesis new cyclopropane derivatives via reaction, followed diastereoselective acetylation, whereas an a...

SYNTHESIS 2010, No. x, pp 000A–000Exx.xx.2010 Advanced online publication: xx.xx.2010 DOI: 10.1055/s-0029-1218741; Art ID: P00610SS © Georg Thieme Verlag Stuttgart · New York Abstract: A total synthesis of the naturally occurring dihydropyranone dodoneine is reported. The combination of a highly catalytic enantioselective allylboration and a highly diastereoselective allylstannation was used fo...

The jatrophane diterpene Pl-3, isolated in 2003 from Euphorbia platyphyllos, is a structurally complex natural product with highly promising biological properties that include pronounced antiproliferative activity and the inhibition of the efflux-pump activity of multidrug resistance p-glycoprotein. Herein, the synthesis of the eastern fragment of Pl-3 is outlined. The target compound is synthe...