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Free keywords:
trans-hydrogenation; internal alkynes; nocardia sp; palladium; alkoxycarbonylation; ketones; carbamoylation; complexes; catalysis; aldehydes
Abstract:
Alkenyltin derivatives flanked by a hydroxyl group are subject to methoxycarbonylation when treated with catalytic amounts of Pd(OAc)2 and Ph2As in MeOH under a CO atmosphere; key to success is the use of 1,4-benzoquinone as a stoichiometric oxidant in combination with trifluoroacetic acid as a cocatalyst. The acid lowers the LUMO of the quinone and likely marshals the critical assembly of the substrates. Under the optimized conditions, competing proto-destannation is marginal; the method proved compatible with various (acid sensitive) functional groups and was applied to a short formal total synthesis of the antibiotic tubelactomicin A.
