Through-bond transmission of polar substituent effects in the bicyclo [2.2.2]octane ring system as monitored by 119Sn NMR chemical shifts: A 119Sn NMR study of 10-substituted 9-trimethylstannyltriptycenes

✍ Scribed by William Adcock; V. Sankar Iyer

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 508 KB
• Volume: 29
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260290416

✦ Synopsis

Abstract

A series of 10‐substituted(X)‐9‐trimethylstannyltriptycenes (2a) were synthesized and characterized and the ^119^Sn chemical shifts measured. Comparisons were made of the ^119^Sn substituent chemical shifts (SCS) of 2a and the corresponding values of 4‐substituted(X)bicyclo[2.2.2]oct‐1‐yltrimethylstannanes (1a), which confirm the previous conclusion that ‘through‐three‐bond’ effects or double‐hyperconjugation strongly regulate the ^119^Sn shifts of the latter system. A more restricted series of 10‐substituted(X)‐9‐methyltripycenes (2c) were acquired and their ^13^CH~3~SCS compared with those of the corresponding bicyclo[2.2.2]octanes (1c). Significant ‘through‐bond’ contributions are also indicated for the latter system.