diboron trioxide; oxygen 1.) 45 deg C, 60 h, 2.) 110 deg C, 2 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

&nbsp;(i) nBuLi, Me₂NCH₂CH₂NMe₂, (ii) /BRN= 1738107/, (iii) NaOMe;&nbsp;&nbsp;Multistep reaction;&nbsp;<br /> &nbsp;