Development of efficient and selective processes to access enantioenriched organosilanes are highly desirable in enantioselective synthesis and material science. In addition, catalytic enantioselective construction of silicon-stereogenic centers have attracted increasing attention, as the silicon-stereogenic center can induce significant alteration of the biological and physicochemical properties. Strategies for catalytic enantioselective synthesis of chiral silanes containing either a carbon-stereogenic center or a silicon-stereogenic center have been developed, including enantioselective hydrosilylation of unsaturated bonds, desymmetrization of prochiral silanes, and enantioselective silicon-hydrogen bond insertion. However, rare protocols enabled simultaneous construction of a C-stereogenic center and a Si-stereogenic center. Especially it is far more challenging to establish two stereogenic centers via an acyclic transition state through an intermolecular reaction because the flexibility of linear molecules rendered significant difficulty to form an organized transition state and for the chiral catalyst to induce high stereoselectivity.

 

The MENG Fanke group of the State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, has been focusing on the study of novel cobalt-catalyzed asymmetric reactions. In the previous research, they found that conjugated enynes bearing a 1,1-disubstituted alkene could undergo sequential double hydrosilylation of enynes and primary silanes occurred to conform a C-stereogenic center and a Si-stereogenic center simultaneously with high chemo- and stereoselectivity (J. Am. Chem. Soc. 2022, 144, 5233-5240).

 

Recently, new research progress has been made by them. A cobalt-catalyzed protocol for regio-, diastereo- and enantioselective intermolecular hydrosilylation of 1,3-dienes to furnish a wide range of chiral silanes in high efficiency and selectivity. It is the first time that simultaneous construction of a C- and Si-stereogenic center in an acyclic molecule through an intermolecular transformation has been achieved. The unprecedented broad scope of prochiral silanes without the requirement for the installation of specific substituents enabled the access to high diversity on the substituents at the Si-stereogenic center. The catalyst is derived from an inexpensive sustainable cobalt salt and a commercially available bisphosphine. The synthetic utility was demonstrated by reduction of the alkene and stereospecific transformation of the stereogenic Si–H bond, affording a series of useful enantioenriched building blocks that are otherwise difficult to access. Control experiments, deuterium-labeling and kinetic experiments were conducted to elucidate the reaction mechanism, revealing that addition of the Si–Co complex with establishment of the Si-stereogenic center is the rate-determining step.

 

The research outcome has been reported on （Angew. Chem. Int. Ed. 2022, e202205624）and this work was financially supported by National Natural Science Foundation of China, SIOC and State Key Laboratory of Organometallic Chemistry.

 

MENG Fanke Ph.D.Professor

Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences

Ling Ling Road 345 Shanghai 200032 China

Tel: 0086-21-54925203

Email: mengf@sioc.ac.cn