Enantioselective synthesis of epoxides: sharpless epoxidation of alkenylsilanols

Abstract

Sharpless epoxidation of the alkenylsilanol (6) followed by protodesilylation gave styrene oxide with high enantiomeric excess.

A New Transformation of Silanols. Palladium-Catalyzed Cross-Coupling with Organic Halides in the Presence of Silver(I) Oxide

“…Little attention has been paid to synthetic utilization of silanols, since syntheses and isolation of silanols are considered to be difficult due to their instability to moisture, heat, acid, and base. We have recently reported a facile synthesis of silanols that possess a functional group by alkylative cleavage of a cyclic siloxane with organolithium reagents. , Functional group transformations of the obtained silanols are also documented: cyclopropanation of alkenylsilanols, for example, under the conditions of the Simmons−Smith reaction using Et 2 Zn−CH 2 I 2 is accelerated as observed with allylic alcohols. , …”

Catalytic epoxidation of cyclic vinylsilanes by ruthenium(II) complexes under aerobic conditions

“…The presence of the trialkylsilyl group provides regioselective control in the opening of epoxide by a variety of nucleophiles. 8 Also it can be removed under extremely mild conditions to afford epoxides 9 which in some cases are difficult targets by direct synthetic transformations. Further, the a,b-epoxy silanes can be used as "vinyl cation" equivalents 10 synthetic intermediates.…”

Oxygen-promoted coupling of arylboronic acids with olefins catalyzed by [CA]2[PdX4] complexes without a base

“…Despite its high potential and many applications, this reaction has some drawbacks such as harsh reaction conditions, the requirement of an inert atmosphere, and the generation of hydrogen halide as a byproduct [1][2][3][4][5][6][7][8][9][10]. In addition to the conventional Heck reaction, olefins can also be arylated by the use of nucleophilic organometallic reagents such as aryl derivatives of silicon [11][12][13][14], antimony [15], and tin [16][17][18][19][20]. Unfortunately, these organometallic reagents and their byproducts are highly toxic and difficult to separate from the final product.…”