Photo-induced radical borylation of hemiacetals via C–C bond cleavage
作者:Qianyi Liu、Jianning Zhang、Lei Zhang、Fanyang Mo
DOI:10.1016/j.tet.2020.131867
日期:2021.1
In this study, we reported a photo-induced radical borylation of hemiacetal derivatives via C–Cbondcleavage. This transformation can be realized under mild conditions with simple reaction settings and irradiation of visible light. A series of substrates, including both cyclic and linear hemiacetal derivatives, were effectively transformed to the borylation product in moderate to good yields. Finally
Titanocene-Catalyzed Reduction of Lactones to Lactols
作者:Xavier Verdaguer、Marcus C. Hansen、Scott C. Berk、Stephen L. Buchwald
DOI:10.1021/jo971560s
日期:1997.11.1
A convenient method for the conversion of lactones to lactols is described. The hydrosilylation to lactols is carried out via air-stable titanocene difluoride or a titanocene diphenoxide precatalyst using inexpensive polymethylhydrosiloxane (PMHS) as the stoichiometric reductant. These procedures have been demonstrated with a variety of substrates and proceed in good to excellent yield.
Lactols reacted with enol acetates by a Lewis acid reagent, derived from N-chlorosuccinimide and tin(II) chloride, to produce 2-acetonyl cyclic ethers diastereoselectively.
Studies on the Mechanism, Selectivity, and Synthetic Utility of Lactone Reduction Using SmI<sub>2</sub> and H<sub>2</sub>O
作者:Dixit Parmar、Lorna A. Duffy、Dhandapani V. Sadasivam、Hiroshi Matsubara、Paul A. Bradley、Robert A. Flowers、David J. Procter
DOI:10.1021/ja906396u
日期:2009.10.28
esters and lactones have long been thought to lie outside the reducing range of SmI(2), activation of the lanthanide reagent by H(2)O allows some of these substrates to be manipulated in an unprecedented fashion. For example, the SmI(2)-H(2)O reducing system shows complete selectivity for the reduction of 6-membered lactones over other classes of lactones and esters. The kinetics of reduction has been
作者:M. Rosenberger、D. Andrews、F. DiMaria、A. J. Duggan、G. Saucy
DOI:10.1002/hlca.19720550129
日期:1972.1.31
A novel and general synthesis of δ-lactones fromglutaraldehyde is described. The dialdehyde is first reacted with an alkyl or substituted alkyl Grignard reagent to afford a δ-hydroxyaldehyde in good yield. These aldehydes exist preferentially in the cyclic hemiacetal form (δ-lactols). Oxidation of the latter compounds to give δ-lactones is readily achieved with silver oxide or bromine. The δ-lactols