Silylcyclopropanes by Selective [1,4]-Wittig Rearrangement of 4-Silyl-5,6-dihydropyrans

Synthesis of Spiro[furan-2,1'-isoindolin]-3'-ones from 2-(4-Hydroxybut-1-yn-1-yl)benzonitriles and Aryl Aldehydes under the Action of Triflic Acid

The synthesis of spiro[furan-2,1'-isoindolin]-3'-ones from 2-(4-hydroxybut-1-yn-1-yl)benzonitriles and aryl aldehydes is demonstrated. It involves the initial formation of dihydrofuranylideneisoindolinone via intramolecular sequential Prins and Ritter reactions, followed by the ring opening of the furanyl moiety to generate N-acyliminium ions and alcohols for the final cyclization reaction, and the spiro-cyclic compounds are produced in moderate to good yields. It is a one-pot, three-component reaction in which one new quaternary carbon, two five-membered rings, one C-N bond, two C-O bonds, and one C-C bond are formed. The reaction is carried out with a Brønsted acid from 0 °C to room temperature within a short period of time.

Cu-catalyzed, Mn-mediated propargylation and allenylation of aldehydes with propargyl bromides

A simple, practical, and high chemo-selective method for the synthesis of propargyl alcohol and allenyl alcohols via Cu-catalyzed, Mn-mediated propargylation and allenylation of aldehydes with propargyl bromides has been established. When 3-bromo-1-propyne was conducted under the standard condition, the aldehydes were transformed to the corresponding propargylation products completely, while when 1-bromo-2-pentyne was used, allenic alcohol was the only product. Variety of homopropargyl alcohols and allenyl alcohols were obtained in high yields and the reaction is compatible with broad substrate scopes. In addition, the large-scale reaction could also be proceeded smoothly indicating the potential synthetic applications of this transformation.