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Metalated Nitriles: Stereodivergent Cation-Controlled Cyclizations1.

ABSTRACT: Stereodivergent cyclizations of gamma-hydroxy cyclohexanecarbonitriles are controlled simply through judicious choice of cation in the alkylmetal base. Deprotonating a series of cyclic gamma-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 S(N)2 and S(N)2' displacements.

SUBMITTER: Fleming FF

PROVIDER: S-EPMC2597827 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature

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Metalated Nitriles: Stereodivergent Cation-Controlled Cyclizations1.

Fleming Fraser F FF Wei Yunjing Y Liu Wang W Zhang Zhiyu Z

Tetrahedron 20080801 32

Stereodivergent cyclizations of gamma-hydroxy cyclohexanecarbonitriles are controlled simply through judicious choice of cation in the alkylmetal base. Deprotonating a series of cyclic gamma-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 consiste ...[more]

PMID: 19657380

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