Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

• Rudolf Knorr and
• Barbara Schmidt

Beilstein J. Org. Chem. 2018, 14, 3018–3024, doi:10.3762/bjoc.14.281

• carbonyl addition; shielded acrylonitrile; Introduction A carbanionic fragment shows nucleofugal behavior on breaking its single-bond connection with a developing electrophilic center. Apart from deprotonation reactions or formation of a separated ion pair and other trivial examples, the (at least

• ) and (c) with the focus on some nucleofugal traits of the carbanion unit of the stable [4], β-shielded α-metalated acrylonitriles. Results and Discussion The α-cyanoalkenyllithium 2Li (top line of Scheme 2) may be prepared [4] either by LDA-mediated deprotonation (LDA = iPr2NLi) of the β-shielded

• acrylonitrile derivative 1 or by an Sn/Li transmetalation reaction of n-butyllithium (“n-BuLi”) with the α-stannyl derivative 3. Due to intermolecular LiN coordination, 2Li was deduced [4] to form a clustered ground state that showed no obvious rate anomaly with previously [4] studied electrophiles; this should