Silylation of Alcohols, Phenols, and Silanols with Alkynylsilanes – an Efficient Route to Silyl Ethers and Unsymmetrical Siloxanes

Abstract

The formation of several silyl ethers (alkoxysilanes, R3Si‐OR') and unsymmetrical siloxanes (R3Si‐O‐SiR'3) can be catalyzed by the commercially available potassium bis(trimethylsilyl)amide (KHMDS). The reaction proceeds via direct dealkynative coupling between various alcohols or silanols and alkynylsilanes, with a simultaneous formation of gaseous acetylene as the sole by‐product. The dehydrogenative and dealkenative coupling of alcohols or silanols are well‐investigated, whilst the utilization of alkynylsilanes as silylating agents has never been comprehensively studied in this context. Overall, the presented system allows the synthesis of various attractive organosilicon compounds under mild conditions, making this approach an atom‐efficient, environmentally benign, and sustainable alternative to existing synthetic solutions.

Transition Metal‐Free Catalytic C−H Silylation of Terminal Alkynes with bis(Trimethylsilyl)acetylene Initiated by KHMDS

“…As shown in Scheme 2, the late‐stage derivatization was performed, successfully providing two sila‐drug analogs, 5 a and 5 b , in excellent yields (91‐96 %). Importantly, the NH moiety was remained during the reaction, confirming the high chemoselectivity of this strategy (and our previous investigations) [44] …”

“…Importantly, the NH moiety was remained during the reaction, confirming the high chemoselectivity of this strategy (and our previous investigations). [44] Next, we sought to obtain silylated diynes, which can be subsequently used in polymer chemistry. Using our catalytic system, three trimethylsilylated (Scheme 3), symmetrical variants were afforded (7 a-7 c, 76-90 % yield).…”

Cobalt‐Catalyzed Dehydrogenative C−H Silylation of Alkynylsilanes

“…Alkynylsilanes (silylacetylenes) are very important species [1] that can be used in a plethora of relevant transformations (such as protection of reactive groups [2] and carbon–carbon bond formations [3] ). There are several methods for their synthesis, by using halosilanes, [4] silylamines, [5] silyl triflates, [6] and, more recently, silyl alkynoates.…”

Recent advances in catalytic silylation of hydroxyl‐bearing compounds: A green technique for protection of alcohols using Si–O bond formations

“…[1][2][3][4] In this sense, a wide variety of protective groups have been developed. [4][5][6][7][8] There are different requirements which must be fulfilled by a protective group [9][10][11][12][13] ; including the following: (1) In order to have a protected substrate, it must selectively react in good yield [14] ; (2) it should be selectively removed in good yield by available, nontoxic reagents by which the regenerated functional group is not attacked [15,16] ; (3) it must form a derivative being able to be separated from side products related to its formation or cleavage [17,18] ; and (4) with the aim of avoiding more sites of reaction, it must possess a minimum of additional functionality. [19] Moreover, one should pay attention to the fact that no protective group is the best protective group.…”