Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

• Tobias Fiedler,
• Michał Barbasiewicz,
• Michael Stollenz and
• John A. Gladysz

Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211

• ; crystal structures; homeomorphic isomerization; hydrogenation; in/out isomers; metathesis; phosphine boranes; Introduction We have found that a variety of metal complexes with trans-phosphine ligands of the formula P((CH2)mCH=CH2)3 (1; m = 4–14) undergo threefold interligand ring closing alkene

• –19% yields. This is slightly better than the combined yield of in,out- and (in,in/out,out)-2·2BH3 in Scheme 5, although the data are not strictly comparable as the ring sizes differ. It has not yet proved possible to efficiently separate the in/out isomers of 15 and 16. However, byproducts derived