Macrocyclic siloxanes with two exocyclic trans-silanol and two exocyclic trans-amino functions - Stereoselective syntheses and structures

A simple preparative method for the stereoselective synthesis of ten- and t welve-membered cyclosiloxanes with two exocyclic trans-silanol and two exoc yclic trans-amino functions has been developed. Thus, treatment of trimetho xy(morpholinomethyl)silane (5) with two molar equivalents of HOPh2Si-SiPh2O H and HOPh2Si-O-SiPh2OH, respectively, yielded trans-1,6-bis(2-hydroxy-1,1, 2,2-tetraphenyldisilan-1-yloxy)-1, 6-bis(morpholinomethyl)-3,3,4,4,8,8,9,9- octaphenyl-2,5,7,10-tetraoxa-1,3,4,6,8,9-hexasilacyclodecane (6, 10-membere d ring) and trans-2,8-bis(3-hydroxy-1,1,3,3-tetra-phenyldisiloxan-1-yloxy)- 2,8-bis(morpholinomethyl)-4,4,6,6,10,10,12,12-octaphenylcyclohexasiloxane ( 7, 12-membered ring). In contrast, treatment of 5 with two molar equivalent s of HOPh2C-CPh2OH afforded (morpholiniomethyl)bis[tetra-phenylethane-1,2-d iolato(2-)]silicate (3), a zwitterionic spirocyclic,lambda Si-5-silicate. C ompounds 3, 6 . EtOAc, and 7 . PhMe were characterized by elemental analyse s (C, H N), solid-state Si-29 VACP/MAS NMR studies, solution NMR experiment s (H-1, C-13, Si-29; CDCl3), and crystal structure analyses.