Rapid Preparation of Variously Protected Glycals Using Titanium(III)

Abstract

Glycosyl chlorides and bromides can be rapidly converted to glycals in high yield by reaction with (Cp 2 Ti[III]Cl) 2 . This reagent tolerates a wide range of common carbohydrate protecting groups, including silyl ethers, acetals, and esters; the methodology provides a general route for the preparation of glycals substituted with both acid-and base-labile functionality. A reaction mechanism is proposed that is based on heteroatom abstraction to give an intermediate glycosyl radical. This radical reacts with a second equivalent of Ti(III) to yield a glycosyltitanium(IV) species. β-Heteroatom elimination from the glycosyltitanium(IV) complex gives the glycal.

Chemical investigations in the synthesis of O-serinyl aminoribosides

“…1 H NMR data, chemical shift and coupling constants, for H1 of a and b-anomers of the fluorinated derivatives 16 and 17 and the glycosylated products[18][19][20][21][22] …”

Electrochemical Evaluation of Titanocenes in Ionic Liquids with Non‐coordinating and Coordinating Anions and Application for NH3 Synthesis

“…1‐Butyl‐1‐methylpyrrolidinium triflate, Pyr 4 OTf, was synthesized according to the literature, based on the metathesis reaction of 1‐butyl‐1‐methylpyrrolidinium chloride and lithium triflate (Wako Pure Chemical Industries Ltd.), where 1‐butyl‐1‐methylpyrrolidinium chloride was also synthesized according to the literature by using N ‐methylpyrrolidine (TCI Co. Ltd) distilled with KOH under an N 2 atmosphere and 1‐chlorobutane (TCI Co. Ltd) distilled from CaH 2 under an N 2 atmosphere. Bis[(dicyclopentadienyl)titanium(III) chloride], [(Cp 2 TiCl) 2 ] ( 2 ) was synthesized according to the literature . [Cp 2 TiCl 2 ] ( 1 ), [(Cp 2 TiCl) 2 ] ( 2 ) and ionic liquids were stored in a glove box (mBRAUN MB 150B‐G glovebox) under an Ar atmosphere (<1 ppm O 2 /H 2 O).…”

“…Accordingly, we estimated that the active intermediate generated in electrochemical reduction of [Cp 2 TiCl 2 ] ( 1 ) in SPE cell is monomeric [Cp 2 TiCl] ( 3 ) that was examined in our previous study . [(Cp 2 TiCl) 2 ] ( 2 ) was prepared by chemical reduction in the previous study, and therefore, the generation of [Cp 2 TiCl] ( 3 ) in Pyr 4 FAP by electrochemical reduction of [Cp 2 TiCl 2 ] ( 1 ) in Pyr 4 FAP is required to be confirmed.…”

Bis(cyclopentadienyl)titanium(III) Chloride

“…39 As with the vicinal dibromides, these reactions are believed to proceed via two discrete one-electron processes. 36-38 While these reactions can be run with stoichiometric Cp 2 TiCl, they are well suited to the catalytic protocol.…”