Stereoselective geminal difunctionalization of vinyl arenes mediated by the bromonium ion

Abstract

An anti-Markovnikov geminal oxyamination of styrenyl alkenes in an intermolecular fashion using the umpolung strategy mediated by the bromonium ion is reported. Isotope labeling studies confirm the migration of the phenyl group in the semipinacol rearrangement.

An Efficient Synthesis of Oxazolidines by Tandem Ring‐Opening / Closing Reaction of Ts‐Aziridine Using Formic Acid

“…To prove the synthetic utility of this method, the ring opening product (i. e. formate ester 5 a ) could be transformed to the corresponding hydroxyl compound ( 6 ) without any difficulty by applying a common hydrolysis method (Scheme ). The amino hydroxyl derivatives are key building blocks for the synthesis of heterocycles ,. Again it is worthy to mention that the corresponding formate ester ( 5 ) is not converted to ( 4 ) on reaction with formaldehyde and for acid under similar reaction condition as shown in scheme b.…”

“…The amino hydroxyl derivatives are key building blocks for the synthesis of heterocycles. [10,16] Again it is worthy to mention that the corresponding formate ester (5) is not converted to (4) on reaction with formaldehyde and for acid under similar reaction condition as shown in scheme 1b.…”

“…Chandrasekaran et al . reported a non‐Wacker process for geminal oxyamination of alkenes using amino alcohol and alkene which afforded 1,3‐oxazolidines . Very recently, we reported one pot conversion of aziridine to the corresponding ring opening product ( N ‐Ts‐phenylalaninol) followed by its addition to the double bond to get the 5‐membered oxazolidine derivatives (Scheme a) …”

Chiral‐Organotin‐Catalyzed Kinetic Resolution of Vicinal Amino Alcohols

“…Further optimization of the reaction conditions by changing the solvent, the reaction temperature, base, and electrophile failed to afford better results. The absolute configuration of 1 e was unambiguously assigned to be ( R ) …”

One‐Pot Synthesis of Oxazolidine Derivatives by [3+2]‐Annulation Reactions of 1‐Tosyl‐2‐phenyl/alkylaziridines with Aryl Epoxides

“…[4] Owing to their biological activities, development of new synthetic protocols for polysubstituted oxazolidine derivatives is of greater interest. [7] In addition, the reactivity of epoxides in the presence of Lewis acid catalysts is excellent.T hey mainly undergo CÀOb ond cleavage and rearrangements, such as the Meinwaldr earrangement. [6] Recently,C handrasekaran and Balaji disclosed an approachfor the brominium ion mediated functionalization of vinyl arenes toward oxazolidine synthesis (Scheme1,a pproach 2).…”