Alkenyl boronate complexes react with acylated quinolines and isoquinolines via 1,2-metalate rearrangement to give alkylated, dearomatized heterocycles in good yields, diastereoselectivities, regioselectivities. This multi-component coupling is highly modular can be used access a wide scope of heterocyclic scaffolds. Chiral boronic esters made through this methodology possess high synthetic pot...

Racemic boronate-imine and boronate-amine complexes 8 and 10, both featuring a stereogenic boron atom were synthesized from 2-amino-1,1-diphenylethanol (5) and characterized by crystal structure analyses. Proof of enantiomerism at the boron center for the novel boronate-amine complex 10 was established by separation of the enantiomers. Racemization barriers were found to be in the same range fo...

A method was developed for the synthesis of α-alkyl, α-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the correspo...

[reaction: see text] By synthesizing two possible diastereomers, the first asymmetric total synthesis of synerazol, an antifungal antibiotic, has been accomplished, allowing determination of its absolute stereochemistry. A more practical second generation route was also established. The key steps are racemization-free deprotection of a TIPS group and introduction of a methyl ether by DMD oxidat...

INTRODUCTION............ 449 PROPERTIES OF PEPTIDE ANTIBIOTICS 449 FORMATION OF ANTIBIOTICS IN RELATION TO GROWTH ...... ............ 450 CELL-FREE SYNTHESIS OF PEPTIDE ANTIBIOTICS ...... .................. 451 ENZYMATIC SYNTHESIS OF GRAMICIDIN S ........ ......................... 451 ENZYMATIC FORMATION OF TYROCIDINE ........ ......................... 453 LINEAR GRAMICIDINS ......................

In this work, a racemization method of (S)-1-phenylethanol by niobium salts was developed. Among the available, phosphate hydrate (NbOPO4.nH2O) reduced enantiomeric excess (ee) chiral alcohol from 95 to 0% after 24 h at 60 ºC in toluene. This new agent combined with lipase (CALB) order achieve chemoenzymatic dynamic kinetic resolution (DKR). Experiments demonstrated that DKR process is feasible...