Synthesis of highly substituted allenylsilanes by alkylidenation of silylketenes

• Stephen P. Marsden and
• Pascal C. Ducept

Beilstein J. Org. Chem. 2005, 1, No. 5, doi:10.1186/1860-5397-1-5

• carbenoid-based reagents. Introduction Allenylsilanes are versatile intermediates for organic synthesis.[1][2] They have two main modes of reactivity: firstly, as propargyl anion equivalents in thermal [3][4] or Lewis acid-mediated [5][6] addition to carbonyls, acetals and imines, and secondly as three

Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

• Andrew Kennedy,
• Adam Nelson and
• Alexis Perry

Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2

• products were converted into the corresponding methyl N,O and O,O acetals 28 and 32. As has previously been observed,[34][35][36][37][38][48][49] the relative configuration of the N,O acetals was completely controlled (2,6cis:2,6trans >95:<5) and that of the O,O acetals was poorly controlled (2,6cis

• .) For the syntheses of the allylated and reduced substrates, the crude products were treated directly with boron trifluoride etherate and either allyltrimethylsilane or triethylsilane. It was possible to switch cleanly to a one-directional synthesis because the N,O acetals were much more susceptible to