(S)-4-Benzyl-2-oxazolidinone

Wittig Rearrangements of Boron-Based Oxazolidinone Enolates

“…A combination of spectroscopic and computational studies helped us understand the structures of the intermediates along the reaction coordinate (Scheme ) and guided us to a functional protocol where none seemed to exist in the early stages. The intermediate enolate, chelated by the alkoxy moiety rather than the oxazolidinone carbonyl, is common to a number of boron-based aldol additions of such α-alkoxy Evans enolates. , …”

“…The consequences to stereochemistry would be considerable and pose some challenging but interesting questions. Second, our interest in the chemistry of oxazolidinone-derived Evans enolates previously revealed that, while the lithium enolates in THF are highly aggregated, TMEDA-solvated sodium enolates are monomeric, raising the prospect of probing aggregation effects from two extremes. Lastly, there are no reports that describe the use of the Evans oxazolidinone auxiliaries for such [2,3]-sigmatropic rearrangements …”

“…After briefly exploring titanium enolates with little luck, we were naturally drawn to boron enolates, owing to reports of boron-based [2,3]-sigmatropic rearrangements on simpler systems, boron-based aldol additions of Evans enolates including α-alkoxy cases, , and our previous structural and mechanistic studies of the boron-based Evans enolates. , …”

Evans Enolates: Structures and Mechanisms Underlying the Aldol Addition of Oxazolidinone-Derived Boron Enolates

“…Although their first attempts likely involved alkali-metal enolates, boron enolates derived from di- n -butylboron triflate ( n -Bu 2 BOTf) provide exceptional diastereoselectivities (eq ). Since that first publication, Evans enolates have been reported in an astonishing 1600 patents …”

An Asymmetric Vinylogous Michael Cascade of Silyl Glyoximide, Vinyl Grignard, and Nitroalkenes via Long Range Stereoinduction

“…Compared to other vinylogous Michael methodologies, silyl glyoximides offer a conceptually distinct approach to the requisite dienolate nucleophile via a [1,2]-Brook rearrangement that provides α-heteroatom functionality currently inaccessible through other methods (Scheme ). The three-component coupling yields densely functionalized compounds, providing an enolsilane, nitro group, and acyl oxazolidinone in the product.…”