A highly efficient diastereo- and enantioselective Mannich reaction of lactones with a variety of N-Boc-aldimines by using bifunctional rosin-derived amine thiourea catalysts was investigated for the first time, in general, affording the adducts bearing quaternary stereogenic centers with high levels of enantio- and diastereoselectivity (up to 99% ee, and >20:1 dr).

[structure] A catalytic asymmetric reaction process was designed involving the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, yielding pure product after crystallization with exceptional enantio- and diastereoselectivity.

The first catalytic asymmetric carbonyl ylide cycloaddition with arylallenes is described. With dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, the cycloaddition of carbonyl ylides derived from diazoketoesters with arylallenes proceeded in a fully chemo- and regioselective manner to give highly functionalized 8-oxabicyclo[3.2.1]octanes with up to 99% ee and pe...

Schinortriterpenoids, such as pre-schisanartanin A and arisanlactone C, are complex highly oxygenated polycyclic terpenes. In this study, the left-hand fragment of class terpenes, which possesses oxygen-functionality at C19, was synthesized through [3+2] cycloaddition with excellent diastereoselectivity. This stereoselectivity investigated by computational studies. Further selective transformat...

The first asymmetric intermolecular addition of non-acidic C-H bonds to imines is reported. The use of the activating N-perfluorobutanesulfinyl imine substituent is essential for achieving sufficient reactivity and provides outstanding diastereoselectivity (>98:2 dr). Straightforward removal of the sulfinyl group with HCl yields the highly enantiomerically enriched amine hydrochlorides.

Herein we report an enantioselective synthesis of complex cyclopentanones using aliphatic aldehydes and activated enones. With the combination of a chiral secondary amine and a chiral triazolium catalyst, high diastereoselectivity and excellent enantioselectivity can be achieved. We present evidence of a clear cooperative effect when these two catalysts are present simultaneously in the system.

We report the unexpected formation of a 1-azadiene dimer from 4,6-diphenyl-3,6-dihydro-2H-1,3-thiazine-2-thiones under prolonged microwave irradiation. In this manner, thiazine-2-thiones act as "masked" 1-azadiene equivalents, which makes them useful synthetic tools to access complex heterocyclic frameworks. We compare this dimerization with earlier approaches and elaborate on the observed dias...

The complex OsO4.(S,S)-1,2-diphenyl-N,N'-bis(2,4,6-trimethylbenzyl)ethane-1,2-diamine is an effective reagent for the desymmetrisation of meso-1,2-bis(3,6-dihydro-2H-pyran-2-yl)ethanes by asymmetric dihydroxylation; this process, whose sense of diastereoselectivity depends on substitution and stereochemistry, has been exploited in the synthesis of a C-linked analogue of allolactose.

Total synthesis of cryptocin, a fungus metabolite, was achieved based on the biosynthetic hypothesis. A variety of derivatives of cryptocin, equisetin and fusarisetin A were prepared, wherein the racemization of C-3 and diastereoselectivity of C-5 were investigated. We further examined their inhibitory effects on breast cancer cell survival and metastasis, and summarized the structure-activity ...

Thia-Claisen rearrangements have been carried out using N-benzylpyrrolidine-2-thione and chiral allylic bromides derived from D-mannitol. Introduction of a bromine atom onto the double bond of the allylic bromide reverses the sense of diastereoselectivity in the [3,3]-sigmatropic rearrangement. Density functional theory calculations lead us to rationalise the observed selectivity in terms of a ...