Propellanes. Part LXXXI. Why are tetrakis[organoboranediylbis(oxy)]cyclobutanes formed without a trace of the isomeric tetrakis‐dioxabora[3.3.2]propellanes?

Abstract
MNDO and STO‐3G calculations rationalize the relative instability of the title propellanes vis‐à‐vis the title products that are formed exclusively.