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Pnictogen-bonding catalysis: brevetoxin-type polyether cyclizations.

ABSTRACT: Pnictogen-bond donors are attractive for use in catalysis because of deep ? holes, high multivalency, rich hypervalency, and chiral binding pockets. We here report natural product inspired epoxide-opening polyether cyclizations catalyzed by fluoroarylated Sb(v) > Sb(iii) > Bi > Sn > Ge. The distinctive characteristic found for pnictogen-bonding catalysis is the breaking of the Baldwin rules, that is selective endo cyclization into the trans-fused ladder oligomers known from the brevetoxins. Moreover, tris(3,4,5-trifluorophenyl)stibines and their hypervalent stiborane catecholates afford different anti-Baldwin stereoselectivity. Lewis (SbCl₃), Brønsted (AcOH) and ? acids fail to provide similar access to these forbidden rings. Like hydrogen-bonding catalysis differs from Brønsted acid catalysis, pnictogen-bonding catalysis thus emerges as the supramolecular counterpart of covalent Lewis acid catalysis.

SUBMITTER: Gini A

PROVIDER: S-EPMC7690316 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Pnictogen-bonding catalysis: brevetoxin-type polyether cyclizations.

Gini Andrea A Paraja Miguel M Galmés Bartomeu B Besnard Celine C Poblador-Bahamonde Amalia I AI Sakai Naomi N Frontera Antonio A Matile Stefan S

Chemical science 20200625 27

Pnictogen-bond donors are attractive for use in catalysis because of deep σ holes, high multivalency, rich hypervalency, and chiral binding pockets. We here report natural product inspired epoxide-opening polyether cyclizations catalyzed by fluoroarylated Sb(v) > Sb(iii) > Bi > Sn > Ge. The distinctive characteristic found for pnictogen-bonding catalysis is the breaking of the Baldwin rules, that is selective <i>endo</i> cyclization into the <i>trans</i>-fused ladder oligomers known from the bre ...[more]

PMID: 33250977

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