Overarching principles for salting-out extraction are long-established but poorly disseminated. We highlight the opportunity for more widespread application of this technique using the Hofmeister series as a foundational basis for choosing the right salt. The power of this approach is exemplified by the aqueous workup of a highly water-soluble nucleoside in which the use of sodium sulfate allowed for high recoveries without relying on back extraction.

No abstract

No abstract

The bisorbicillinoids are a growing class of novel natural products endowed with unique biological activity and are associated with fascinating hypotheses for their biosynthesis. A full account of our biomimetic explorations toward the bisorbicillinoids including the total syntheses of bisorbicillinol (1), bisorbibutenolide (2), and trichodimerol (4) from sorbicillin (3) is disclosed. Utilizing the novel dimerization reactions discovered and fine-tuned en route to 1 and 4, several analogues of these natural products have been synthesized. Furthermore, studies on the scope of these novel cycloaddition reactions and the isolation of a number of unexpected products along with proposed mechanisms for their formation are reported. These findings add to our knowledge of the largely unexplored chemistry of o-quinols and related aromatic systems.

We have recently reported a series of novel synthetic technologies for the facile construction of complex polycycles, [1] diverse heterocycles, [2] amino-sugars, [3] and a,bunsaturated carbonyl compounds [4] induced by hypervalent iodine reagents (o-iodoxybenzoic acid (1-hydroxy-1,2-benziodoxol-3(1H)-one-1-oxide, IBX) and Dess ± Martin periodinate (DMP)). This spate of reactions, which arose from a discovery made during the total synthesis of the CP molecules, [5] necessitated an in-depth mechanistic investigation to gain further understanding of the sequence of processes involved. Herein we present divergent mechanistic pathways for these IBX-and DMP-mediated reactions based on isotope labeling, kinetic studies, cyclic voltammetry measurements, NMR spectroscopic analysis, and designed cascade reactions.For the IBX-mediated ring closures of anilides and related systems to N-heterocycles, we had previously proposed a pathway predicated on single electron transfer (SET) as shown in Scheme 1 (I 3II 3III 3IV 3V). [3] To confirm this Scheme 1. Proposed mechanism of the IBX-mediated ring closure of anilides and related systems to N-heterocycles (I 3V). SET single electron transfer, IBX o-iodoxybenzoic acid.

Compound 1, a potent and irreversible inhibitor of β-lactamases, is in clinical trials with β-lactam antibiotics for the treatment of serious and antibiotic-resistant bacterial infections. A short, scalable, and cost-effective route for the production of this densely functionalized polycyclic molecule is described.

No abstract

[reaction: see text]. A practical synthesis of sultams was developed via intramolecular sulfonamide dianion alkylation. This method has been applied toward the synthesis of chiral sultams, which are synthetically valuable as chiral auxiliaries.