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Catalytic Hydrothiolation: Counterion-Controlled Regioselectivity.

ABSTRACT: In this Article, we expand upon the catalytic hydrothiolation of 1,3-dienes to afford either allylic or homoallylic sulfides with high regiocontrol. Mechanistic studies support a pathway in which regioselectivity is dictated by the choice of counterion associated with the Rh center. Non-coordinating counterions, such as SbF6-, allow for ?4-diene coordination to Rh complexes and result in allylic sulfides. In contrast, coordinating counterions, such as Cl-, favor neutral Rh complexes in which the diene binds ?2 to afford homoallylic sulfides. We propose mechanisms that rationalize a fractional dependence on thiol for the 1,2-Markovnikov hydrothiolation while accounting for an inverse dependence on thiol in the 3,4- anti-Markovnikov pathway. Through the hydrothiolation of an essential oil (?-farnesene), we achieve the first enantioselective synthesis of (-)-agelasidine A.

SUBMITTER: Yang XH

PROVIDER: S-EPMC6563821 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Catalytic Hydrothiolation: Counterion-Controlled Regioselectivity.

Yang Xiao-Hui XH Davison Ryan T RT Nie Shao-Zhen SZ Cruz Faben A FA McGinnis Tristan M TM Dong Vy M VM

Journal of the American Chemical Society 20190208 7

In this Article, we expand upon the catalytic hydrothiolation of 1,3-dienes to afford either allylic or homoallylic sulfides with high regiocontrol. Mechanistic studies support a pathway in which regioselectivity is dictated by the choice of counterion associated with the Rh center. Non-coordinating counterions, such as SbF6-, allow for η4-diene coordination to Rh complexes and result in allylic sulfides. In contrast, coordinating counterions, such as Cl-</s ...[more]

PMID: 30735362

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