Substituent Effects on 鈥淗yperconjugative鈥?Aromaticity and Antiaromaticity in Planar Cyclopolyenes

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• 作者：Israel Fern谩ndez ; Judy I. Wu ; Paul von Ragu茅 Schleyer
• 刊名：Organic Letters
• 出版年：2013
• 出版时间：June 21, 2013
• 年：2013
• 卷：15
• 期：12
• 页码：2990-2993
• 全文大小：275K
• 年卷期：v.15,no.12(June 21, 2013)
• ISSN：1523-7052

文摘

Computed aromatic stabilization energies (ASEs) and dissected nucleus independent chemical shifts (NICS_蟺zz) quantify the effect of hyperconjugation on the (anti)aromaticities of the planar conformations of three, five, seven, and nine membered (C_nH_n)CR₂ (R = H, SiH₃, F) rings. CH₂ and especially C(SiH₃)₂ groups supply two 鈥減seudo鈥?蟺 electrons hyperconjugatively along with the olefinic 蟺 electrons in the ring, whereas a CF₂ group acts like a partially vacant p orbital. Following the H眉ckel rule, compounds with 4n+2 (or 4n) pseudo 蟺 electrons are 鈥渉yperconjugatively鈥?aromatic (or antiaromatic).