Eribulin Impurity 47

3- ((2S,5S) -5- (2- ((2S,4R,6R) -6- (((2R,3S,4R,5R) -5- ((R) -2,3-bis ((tert-butyldimethylsilyl) oxy) propyl) -4-methoxy-3- (tosylmethyl) tetrahydrofuran-2-yl) methyl) -4-methyl-5-methylenetetrahydro-2H-pyran-2-yl) ethyl) -4-methylenetetrahydrofuran-2-yl) propan-1-ol