High selectivities in electrophilic additions to cyclobutene compounds

✍ Scribed by Laurence Mévellec; Michel Evers; François Huet

• Publisher: Elsevier Science
• Year: 1996
• Tongue: French
• Weight: 1009 KB
• Volume: 52
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(96)00945-3

✦ Synopsis

Epoxidation of 2, 3,4 with m-CPBA mainly led to the cis-attack products whereas 1 and 6 led to the other selectivity. The result was reversed, from 4, with Payne's reagent. Bromohydroxylation of 4 involved an intermediate bromonium ion syn to the substituents. Haloselenylations occurred with the syn-selectivity from 1, 2, 3 and 4, to the anti-selectivity from 6, and without selectivity from 5. NOE enhancement measurements and several chemical correlations led to the stereochemical assignments. Formation of the intmmolecular reaction products 24 and 25 was also pointed out.