A selectivity study of activated ketal reduction with borane dimethyl sulfide
摘要:
A chemo- and regioselectivity study of the reagent combination BH3.SMe2/TMSOTf for ketal reduction has been undertaken. It has revealed that simple 1,3-dioxanes reduce cleanly at low temperature in CH2Cl2 while simple 1,3-dioxolanes may give complete ring cleavage and dimerization products. A study of reduction of 4-substituted 1,3-dioxolanes has revealed a solvent-directed regioselectivity which in THF favors the secondary protected derivative. A mechanism is postulated to account for the selectivities based on recent thinking on acetal substitution reactions.
Synthesis of Acetonides from Epoxides Catalyzed by Erbium(III) Triflate
作者:Antonio Procopio、Renato Dalpozzo、Antonio De Nino、Loredana Maiuolo、Monica Nardi、Beatrice Russo
DOI:10.1002/adsc.200505096
日期:2005.8
Epoxides dissolved in acetone can be converted almost quantitatively in acetonides in the presence of catalytic amounts of erbium(III) triflate. The procedure can be usefully applied to other substrates and can be extended to other ketones.