穴田 仁洋

The total synthesis of breviscapin B, a norlignan natural product having an unusual 2,2-diaryltetrahydrofuran skeleton, has been achieved via intramolecular dehydrative Williamson ether synthesis as a key step.

A one-shot substitution of all hydrogens at the α,β-positions of saturated cyclic amines was achieved. The key feature of this reaction is the sequential involvement of intra- and intermolecular redox processes. When N,O-acetals obtained through an internal redox process were treated with a catalytic amount of Zn(OTf)2 and an excess amount of benzylidene barbiturates, three key transformations involving intermolecular redox process occurred successively to afford α,β-unsaturated lactams in moderate to good chemical yields.

A concise and direct cyanation of secondary and tertiary benzylic and allylic alcohols catalyzed by Brønsted acid has been developed using trimethylsilyl cyanide (TMSCN) as a cyanide source and 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) as a solvent. The present transition metal‐free catalytic process is operationally simple to perform under “open‐flask” conditions and it is applicable to the preparation of a number of α‐arylacetonitriles as well as late‐stage material transformations. The effectiveness of the present protocol was further demonstrated by the first enantioselective synthesis and determination of the absolute configuration of verimol F.