General and Practical One-Pot Synthesis of Dihydrobenzosiloles from Styrenes

Abstract

A one-pot synthesis of dihydrobenzosiloles from styrenes has been developed. The reaction involves the nickel-catalyzed hydrosilylation of styrene with diphenylsilane, followed by the irridium-catalyzed dehydrogenative cyclization. This method is efficient for both electron rich and electron deficient styrenes, and exhibits good functional group tolerance, as well as excellent regioselectivity. The forming dihydrobenzosiloles can be efficiently converted into valuable benzosiloles or 2-hydroxyphenethyl alcohols.

Silicon-Tethered Strategies for C–H Functionalization Reactions

“…37 In 2012, we reported a practical and general one-pot procedure for synthesis of dihydrobenzosiloles 144 from styrenes 142 through the Ni-catalyzed hydrosilylation ( 142 → 143 ), followed by the Ir-catalyzed dehydrogenative cyclization ( 143 → 144 , Scheme 33). 38 This work was inspired by Hartwig’s work in 2005, where the possibility for formation of dihydrobenzosilole from dimethylphenethylsilane via an intramolecular platinum-catalyzed dehydrogenative cyclization reaction was shown ( 140 → 141 ). 39 The scope of the developed transformation ( 142 → 144 ) was found to be quite general, as electronically diverse substituents at various positions of the arenes all reacted well producing the corresponding dihydrobenzosilole products in good yields (Scheme 34).…”

Iron‐Catalyzed Asymmetric Hydrosilylation of 1,1‐Disubstituted Alkenes

“…[20] The silanes 4 were additionally functionalized to form chiral five-membered silyl rings (6) without loss of enantioselectivity using iridium-catalyzed intramolecular dehydrogenation. [21] We determined the absolute configuration of hydrosilylation products by X-ray analysis of the compounds 6 b and 6 v. [22] The phenol derivatives with chiral motifs at the ortho-position are also core structures and useful precursors [23] for bioactive natural products, [24] and 7 b was obtained in 86 % yield by oxidative hydrolysis [20] of the cyclic silane 6 b. Chiral 3-substituted 2,3dihydrobenzofurans [25] are precursors for the anticancer active (À)-thespesone [26] or single-stranded abiotic metallofoldamers. [27] (S)-(+)-3-Methyl dihydrobenzofuran (8 b) was obtained through an intramolecular Mitsunobu reaction [20] of 7 b in 62 % yield (the product was highly volatile).…”

Construction of a Chiral Silicon Center by Rhodium‐Catalyzed Enantioselective Intramolecular Hydrosilylation

“…The products were five-membered organosilanes 7 with achiral silicon stereogenic centers. We expect that these organosilanes 7 can find aplication in the development of silicon-based advancedm aterials such as benzosiloles [2,16] with ac hiral silicon center,f ormed by the oxidation of 7, [17] or silicon polymers, [18] formed by polymerization via the unreacted olefin. It should be also noted that the present enantioselective transformation was successfully conducted only in the presence of our original chiral phen ligand 8,w hich forms an N,N,O-tridentate complex with [{Rh(cod)OMe} 2 ], the structure having been confirmed by Table 2.…”