Synthesis of Bifunctional Allylic Compounds by Using Cyclopropenes as Functionalized Allyl Equivalents

Abstract

The synthesis of uncommon bifunctional allylic derivatives bearing a silane and an alcohol within the same allylic framework is reported. This method relies on the coupling of hydrosilanes with substituted and functionalized cyclopropenes, which deliver the allyl fragment. Rhodium(II) catalysts provide regioselective access to vinyl carbene intermediates, which easily undergo Si-H bond insertions. The transformation occurs with complete atom economy and shows a remarkably broad scope, including a intramolecular version for the synthesis of cyclic O-Si-linked compounds as well as the synthesis of the corresponding allyl amines.

Transition Metal Catalyzed Insertion Reactions with Donor/Donor Carbenes

“…[85] Notably,t his method was applied in GeÀHi nsertion for the first ever zinc-catalyzed insertions into germanium hydrides.Inalater report by Vicente and coworkers,c yclopropene-derived rhodium octanoate (23)c arbenes were used to generate ab road scope of substrates (> 35 examples) via intermolecular Si À Hi nsertion reactions (Figure 19, 163-165). [86] This method was effective at low catalyst loadings (1 mol %) and tolerated other traditionally reactive moieties on the substrate (i.e.p henols,a llyl benzyl groups). Foraspecialized class of substrates,i ntramolecular SiÀHi nsertion reactions were also achieved to produce racemic cyclic siloxanes.W hile these researchers have had considerable success with these diazo-free methodologies, there are still many opportunities to expand substrate scope, further develop enantioselective variants,a nd introduce new orthogonal diazo-free methods.…”

Transition Metal Catalyzed Insertion Reactions with Donor/Donor Carbenes

“…Notably, this method was applied in Ge−H insertion for the first ever zinc‐catalyzed insertions into germanium hydrides. In a later report by Vicente and co‐workers, cyclopropene‐derived rhodium octanoate ( 23 ) carbenes were used to generate a broad scope of substrates (>35 examples) via intermolecular Si−H insertion reactions (Figure 19, 163 – 165 ) [86] . This method was effective at low catalyst loadings (1 mol %) and tolerated other traditionally reactive moieties on the substrate (i.e.…”

Synthetic Applications of Cyclopropene and Cyclopropenone: Recent Progress and Developments

“…The synthesis of alkenes by formal carbene dimerization was well explored. [63,64,58] In 2017, Jianbo Wang's team [65] reported ruthenium(Ru-II)-catalyzed synthesis of tetrasubstituted conjugated diene 124 from cyclopropenes 122 and diazo compounds 123. Homocoupling products were not formed indicating the high selectivity of the substrates towards Ru(II) catalysts.…”