Through-space transmission of polar substituent effects in the bicyclo[1.1.1]pentane ring system as monitored by 119Sn NMR chemical shifts: a 13C and 119Sn NMR study of 3-substituted-(X)bicyclo[1.1.1]pent-1-yltrimethylstannanes

✍ Scribed by William Adcock; Alexander R. Krstic

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 279 KB
• Volume: 35
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199711)35:10<663::aid-omr144>3.0.co;2-7

✦ Synopsis

A series of 3-substituted(X)bicyclo [ 1.1.1 ] pent-1-yltrimethylstannanes (3) were synthesized and their 119Sn and 13C NMR spectra were recorded. The 119Sn substituent chemical shifts (SCS) and the one-bond carbon-tin coupling constants [ 1J(13C,119Sn) ] were analyzed in terms of possible substituent-probe interactions. The study clearly reveals that the 119Sn NMR parameters of 3 are remarkably sensitive to modulation of the through-space back-or rear-lobe interactions between the bridgehead bond molecular orbitals by the electronic character of the substituent. An extraordinarily large four-bond tin-tin coupling constant in 3 highlights the signiÐcance of (X = SnMe 3 ) through-space bridgehead-bridgehead interactions in this system.