Selective Formation of Functionalized α-Quaternary Malononitriles toward 5,5-Disubstituted Pyrrolopyrimidinones.
Alan WhiteheadYong ZhangJamie McCabe DunnEdward C ShererColin Yu-Hong LamJohn StelmachAaron SunMelisa ShirodaRobert K OrrSherman T WaddellSubharekha RaghavanPublished in: Organic letters (2017)
A modular, selective approach to complex α-tertiary substituted malononitriles is reported. The method takes advantage of β-ester-substituted α,α-dinitrile alkenes as highly reactive, chemoselective electrophiles for 1,4-additions with organometallic nucleophiles to produce functionally and sterically dense all-carbon quaternary centers. In the presence of a chiral ester auxiliary bearing an aromatic ring, the 1,4-addition occurs with good to excellent selectivity due to favorable cation-π interactions. The highly functionalized malononitriles represent versatile building blocks and can be applied toward efficient, highly selective syntheses of 5,5-disubstituted pyrrolopyrimidinones.