Functionalized Silyl-BINOLs and their Use as Building Blocks for the Synthesis of Chiral Sila-Macrocycles.

Abstract

The axially chiral 1,1'-bi-2-naphthol (BINOL) have been used as starting material to produce chiral organosilanes in moderate to excellent yields. Among them, hydrosilanes (S)-6,6'-bis(dimethylsilyl)-2,2'-dimethoxy-1,1'-binaphthyl (26), (S)-3,3'-bis(dimethylsilyl)-2,2'-dimethoxy-1,1'-binaphthyl (30), and (S)-4,4'-bis(dimethylsilyl)-6,6'-dichloro-2,2'-dimethoxy-1,1'-binaphthyl (35) are reported. These compounds were further converted into their respective silanols, (S)-6,6'-bis(dimethylhydroxysilyl)-2,2'-dimethoxy-1,1'-binaphthalene (26a), (S)-3,3'-bis(dimethylhydroxysilyl)-2,2'-dimethoxy-1,1'-binaphthalene (30a), and (S)-6,6'-dichloro-4,4'-bis(dimethylhydroxysilyl)-2,2'-dimethoxy-1,1'-binaphthalene (35a) by oxidation in the presence of Pearlmans catalyst in water. Also, chlorination of hydrosilanes 26, 30, and 35 with carbon tetrachloride and palladium dichloride afforded chlorosilanes (S)-6,6'-bis(dimethylchlorosilyl)-2,2'-dimethoxy-1,1'-binaphthalene (26b), (S)-3,3'-bis(dimethylchlorosilyl)-2,2'-dimethoxy-1,1'-binaphthalene (30b), and (S)-6,6'-dichloro-4,4'-bis(dimethylchlorosilyl)-2,2'-dimethoxy-1,1'-binaphthalene (35b) in quantitative yields. Additionally, the synthesis and characterization of novel vinylsilanes (S)-6,6'-bis(dimethylvinylsilyl)-2,2'-dimethoxy-1,1'-binaphthalene (27), (S)-3,3'-bis(dimethylvinylsilyl)-2,2'-dimethoxy-1,1'-binaphthalene (31), and (S)-6,6'-dichloro-4,4'-bis(dimethylvinylsilyl)-2,2'-dimethoxy-1,1'-binaphthalene (36) is described. Other chiral organosilanes containing chloromethylsilane groups were synthesized, from which novel compounds bearing organotin moieties were afforded. Besides, chiral sila-macrocycles were prepared using the above mentioned chiral organosilane building blocks. Thus, cyclic siloxanes (S,S)-2,2',10,10'-tetramethoxy-1,1',9,9'-bis(binaphthyl)-6,6',14,14'-octamethyltetrasiloxane (38) and (S,S)-2,2',10,10'-tetramethoxy-1,1',9,9'-bis(binaphthyl)-3,3',11,11'-octamethyltetrasiloxane (39) were obtained from hydrosilanes (26 and 30) or silanols (26a and 30a). Novel macrocycles (S,S)-2,2',10,10'-tetramethoxy-1,1',9,9'-bis(binaphthyl)-6,6',14,14'-octamethyldiethylsilane (41) and (S,S)-2,2',10,10'-tetramethoxy-1,1',9,9'-bis(binaphthyl)-3,3',11,11'-octamethyldiethylsilane (42) possessing an aliphatic bridge were conveniently prepared via hydrosilylation reaction of vinylsilanes (27 and 31) with hydrosilanes (26 and 30) using Karstedt catalyst, respectively. In addition, chlorosilanes (26b and 30b) were used to prepare macrocycles connected by an aromatic ligand. Besides, functionalization of macrocycles 38 - 42 by demethylation, bromination, and silylation was attempted.