FUNCTIONALIZED CARBOCYCLES FROM CARBOHYDRATES. PART 7. A ROUTE TO CARBACYCLIN N FROM A D-GLUCOSE DERIVATIVE. X-RAY CRYSTAL STRUCTURE OF 3-ENDO-BENZOYLOXY-2-EXO-(1,3-DIPHENYL-1,3,2-DIAZAPHOSPHOLAN-2-YLOXYMETHYL)-6-OXOBICYCLO(3.3.0)OCTA