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A detailed study of a room-temperature asymmetric Diels-Alder reaction of N-sulfonyl-1-aza-1,3-butadienes reports the series of 19 enol ethers bearing chiral auxiliaries with many providing highly diastereoselective reactions, largely the result of an exquisitely organized (4+2) cycloaddition transition site. Three readily accessible and unexplored auxiliaries rationally emerged from the studies and provide remarkable selectivities that promise to be useful in systems.

Synthesis process is described for a short and highly efficient manufacturing process of coenzyme Q10 (CoQ10). Synthetic CoQ10 was identical to authentic material in all respects and the typical impurities were completely averted during the synthetic process.

An efficient synthesis of two diastereomers of the chlorofusin cyclic peptide bearing either the l-Asn3/d-Asn-4 or d-Asn3/l-Asn4 stereochemistry is detailed. Four key subunits were prepared, sequentially coupled, and cyclized to provide the two diastereomeric macrocycles. The absolute stereochemistry at the asparagine residues 3 and 4 was assigned as l and d, respectively, by correlating the NMR data of the two diastereomers with that reported for the natural product. [structure: see text]

[structure: see text] Using the "lactone concept", differently substituted AB-biaryl fragments (P)-2 (R = Me, t-Bu) of vancomycin have been synthesized atroposelectively. Their otherwise configurational instability was remedied by inclusion of two chlorine atoms in the B ring to give (M)-29. Starting from a still configurationally unstable lactone-bridged precursor, we obtained this biaryl with high atroposelectivity (dr 94:6) by ring cleavage with dynamic kinetic diastereomeric resolution.