(6aR,8R,9S,9aR)-tert-butyl 9-hydroxy-2,2,4,4-tetraisopropyl-8-(2-(methylamino)-2-oxoethyl)tetrahydro-[ 1,3,5,2,4]trioxadisilocino [7,6-b]pyrrole-7(8H)-carboxylate