Synthesis of Cyclopropenes via
1,2-Elimination of Bromocyclopropanes Catalyzed by Crown
Ether
作者:Michael Rubin、William Sherrill、Ryan Kim
DOI:10.1055/s-0028-1088122
日期:——
synthetic protocol for the preparation of 3,3-disubstituted cyclopropenes from the corresponding bromocyclopropanes via a base-assisted 1,2-elimination has been developed. Employment of catalytic amounts of 18-crown-6 in ethereal solvents allowed for improved yields, as compared to the classical procedure employing dimethyl sulfoxide, making this protocol applicable to the synthesis of hydrophilic cyclopropenes
Construction of All‐Carbon Chiral Quaternary Centers through Cu
<sup>I</sup>
‐Catalyzed Enantioselective Reductive Hydroxymethylation of 1,1‐Disubstituted Allenes with CO
<sub>2</sub>
construction of all-carbon chiral quaternary centers through reductive hydroxymethylation of 1,1-disubstituted allenes with CO2 has been developed. In the presence of a copper/Mandyphos catalyst, CO2 is transformed into an alcohol oxidation level by an asymmetric reductive C-C bond formation with allenes by using hydrosilane (HSi(OMe)2 Me) as a reductant. The resulting chiral homoallylic alcohols are