Enantioselective Construction of Si‐Stereogenic Center via Rhodium‐Catalyzed Intermolecular Hydrosilylation of Alkene

Abstract

Catalytic, enantioselective synthesis of stereogenic silicon compounds remains a challenge. Herein, we report a rhodium‐catalyzed regio‐ and enantio‐selective intermolecular hydrosilylation of alkene with prochiral dihydrosilane. This new method features a simple catalytic system, mild reaction conditions and a wide functional group tolerance.

Cobalt‐Catalyzed Regio‐, Diastereo‐ and Enantioselective Intermolecular Hydrosilylation of 1,3‐Dienes with Prochiral Silanes

“…Our studies commenced with reaction of simple 1,3‐diene 1 a with methylphenylsilane 2 a in the presence of Co complexes derived from various chiral phosphine ligands (Table 1). Unlike previous hydrosilylation of alkenes and alkynes with a limited scope of prochiral silanes, [7r, 8q–s] we expected that high stereoselectivity could be achieved for diversified prochiral silanes without the requirement for installation of a specific substituent. Co complexes generated from bisphosphines 4 a – d could not promote the reaction (entries 1–4).…”

“…Catalytic enantioselective hydrosilylation of unsaturated C−C bonds represents one of the most straightforward and atom‐economical approaches for synthesis of chiral organosilanes. Although metal‐catalyzed protocols for enantioselective hydrosilylation of terminal alkenes, [7b,d–k,m, n] 1,1‐disubstituted alkenes, [7l] 1,3‐dienes, [7s, 12] allenes, [13] cyclopropenes, [7t] vinylcyclopropanes, [7u] gem ‐difluoroalkenes [7v] to furnish a C‐stereogenic center containing a C−Si bond have been revealed (Scheme 1a), more challenging construction of Si‐stereogenic centers through catalytic enantioselective intermolecular hydrosilylation of alkenes and alkynes remained scarce (Scheme 1b) [7r, 8q–s] . Moreover, such processes have significant limitation on the diversity of the prochiral silanes, requiring installation of specific substituents on the silanes.…”

Silicon‐Stereogenic Monohydrosilane: Synthesis and Applications

“…have demonstrated a Rh‐catalyzed intermolecular hydrosilylation of allyl ethers and allyl amines with 69–88 % ee values by employing ( R ) ‐ DM‐Biphep as the chiral ligand (Scheme 18). [35] An oxygen or nitrogen atom on the alkene is required to overcome the low reactivity and regioselectivity issues. Moreover, the use of dihydrosilane 24 is largely limited to (2,6‐dichlorophenyl)(methyl)silane, and replacement of the chloro group by a methyl group led to both low yield and low enantioselectivity ( Si‐18 c vs Si‐18 a , 20 % ee vs 71 % ee ).…”

Enantioselective Construction of Si-Stereogenic Linear Alkenylhy-drosilanes via Copper-Catalyzed Anti-Markovnikov Hydrosilyla-tion of Alkynes

“…[17][18][19][20][21] In fact, the asymmetric catalytic transformation of dihydrosilanes has attracted considerable attention because the obtained chiral product retains a reactive Si-H bond may offer more possibilities for further functionalization. The popular methods of intermolecular desymmetrization of dihydrosilanes to generate silicon-stereogenic silanes include: 1) hydrosilylation of alkenes [27][28][29] , 1,3-dienes 30 , alkynes [31][32][33] and ketones [34][35][36] ; 2) carbenes insertion [37][38][39] ; 3) arylation and dehydrogenative coupling reactions [40][41][42][43][44] ; 4) alcoholysis [45][46][47][48][49][50][51][52][53][54] etc (Scheme 1a).…”