249284-23-9Relevant articles and documents
Generally applicable organocatalytic tetrahydropyranylation of hydroxy functionalities with very low catalyst loading
Kotke, Mike,Schreiner, Peter R.
, p. 779 - 790 (2007)
This paper presents the first acid-free, organocatalytic tetrahydropyran and 2-methoxypropene protection of alcohols, phenols, and other ROH derivatives utilizing privileged N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea and a polystyrene-bound analogue. The reactions are broadly applicably (also on preparative scale), in particular, to acid-sensitive substrates such as aldol products, hydroxy esters, acetals, silyl-protected alcohols, and cyanohydrins. The catalytic efficiency is truly remarkably with turnover numbers of 100,000 and turnover frequencies of up to 5700 h-1 at catalyst loadings down to 0.001 mol%. The computationally supported mechanistic interpretation emphasizes the hydrogen bond assisted heterolysis of the alcohol and concomitant preferential stabilization of the oxyanion hole in the transition state. Georg Thieme Verlag Stuttgart.
Iodine-Catalyzed Mild and Efficient Tetrahydropyranylation/Depyranylation of Alcohols
Kumar, H. M. Sampath,Reddy, B. V. Subba,Reddy, E. Jagan,Yadav, J. S.
, p. 857 - 858 (2007/10/03)
Alcohols and phenols are tetrahydropyranylated rapidly in high yields in the presence of catalytic amount of iodine at room temperature. Depyranylation is effected readily by refluxing with iodine in methanol for few hours.
