Influence of quaternization or coordination of nitrogen with a Lewis acid upon the diastereoselectivity of 5-exo ring closure of β-aminoalkyl radicals

✍ Scribed by M.-P. Bertrand; S. Gastaldi; R. Nouguier

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 658 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)00772-8

✦ Synopsis

Two methodologies, likely to enhance the diastereoselectivity of sultonyl radical mediated cyclization of dienes 8 and 11, were investigated. Quaternization provided the expected result whatever the nature of the radical acceptingdouble bond, so did complexation of 11 with BF 3 or AIMe 3. A more strongly coordinating reagent like BH 3 was necessary to improve selectivity in the case of 8.