450406-20-9Relevant academic research and scientific papers
Metalated nitriles: stereodivergent cation-controlled cyclizations
Fleming, Fraser F.,Wei, Yunjing,Liu, Wang,Zhang, Zhiyu
, p. 7477 - 7488 (2008)
Stereodivergent cyclizations of γ-hydroxy cyclohexanecarbonitriles are controlled simply through judicious choice of cation in the alkylmetal base. Deprotonating a series of cyclic γ-hydroxy nitriles with i-PrMgBr generates C-magnesiated nitriles that cyclize under stereoelectronic control to cis-fused hydrindanes, decalins, and bicyclo[5.4.0]undecanes. An analogous deprotonation with BuLi triggers cyclization to trans-fused hydrindanes, decalins, and bicyclo[5.4.0]undecanes consistent with a sterically controlled electrophilic attack on an equatorial nitrile anion. Using cations to control the geometry of metalated nitriles provides a versatile, stereodivergent cyclization to cis- and trans-hydrindanes, decalins, and [5.4.0]undecanes, and reveals the key geometric requirements for intramolecular SN2 and SN2′ displacements.
Cyclic alkenenitriles: Synthesis, conjugate addition, and stereoselective annulation
Fleming, Fraser F.,Zhang, Zhiyu,Wang, Qunzhao,Steward, Omar W.
, p. 7646 - 7650 (2007/10/03)
O-Alkylation of unsaturated silyl cyanohydrins with DMSO-Ac2O triggers a rearrangement to methylthiomethyl-protected hydroxyalkenenitriles that are easily hydrolyzed for subsequent annulations with ω-chloroalkyl Grignard reagents. Deprotonating the γ-hydroxyalkenenitriles with t-BuMgCl followed by addition of ω-chloroalkyl Grignard reagents triggers a conjugate addition-alkylation sequence leading exclusively to cis-octalins, hydrindanes, and decalins. Stereoelectronic control favors an axial conjugate addition leading to a particularly reactive conformer that rapidly cyclizes to cis-fused bicyclic nitriles, whereas generating the ring-flipped conformer, through a stepwise sequence, allows access to the diastereomeric trans-decalin. Collectively, the rearrangement-annulation sequence represents the first general annulation of alkenenitriles to assemble diverse bicyclic nitriles with complete control over the two newly installed stereocenters.
