The protection of ketones and aldehydes as 4-trimethylsilylmethyl-1,3-dioxolanes
摘要:
The 1,3-dioxolanation of carbonyl compounds with 2,3-bis(trimethylsilyloxy)-trimethylsilylpropane (BTTP) in the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate (TMSOTf) has been investigated. BTTP readily converted unhindered ketones and aldehydes to their corresponding 4-trimethylsilylmethyl-19-dioxolanes, but failed for more hindered substrates. The 4-trimethylsilylmethyl-1,3-dioxolane can be selectively cleaved to regenerate the carbonyl compound in the presence of a 13-dioxolane using either LiBF4 or HF in acetonitrile.
Osmium-Catalyzed Dihydroxylation of Olefins Using Dioxygen or Air as the Terminal Oxidant
作者:Christian Döbler、Gerald M. Mehltretter、Uta Sundermeier、Matthias Beller
DOI:10.1021/ja000802u
日期:2000.10.1
The osmium-catalyzed dihydroxylation of various olefinsusing molecular oxygen or air as the stoichiometric oxidant is reported. Aromatic olefins yield the corresponding diols in good to excellent chemoselectivities under optimized pH conditions (pH = 10.4−12.0). Air can be used under moderate pressures (3−9 bar) instead of dioxygen as the reoxidant. By increasing the oxygen content of the solution
The protection of ketones and aldehydes as 4-trimethylsilylmethyl-1,3-dioxolanes
作者:Brett M. Lillie、Mitchell A. Avery
DOI:10.1016/s0040-4039(00)79941-2
日期:1994.2
The 1,3-dioxolanation of carbonyl compounds with 2,3-bis(trimethylsilyloxy)-trimethylsilylpropane (BTTP) in the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate (TMSOTf) has been investigated. BTTP readily converted unhindered ketones and aldehydes to their corresponding 4-trimethylsilylmethyl-19-dioxolanes, but failed for more hindered substrates. The 4-trimethylsilylmethyl-1,3-dioxolane can be selectively cleaved to regenerate the carbonyl compound in the presence of a 13-dioxolane using either LiBF4 or HF in acetonitrile.
Synthesis of optically active secondary allylic alcohols from allylsilanes via successive asymmetric dihydroxylation (AD) and Peterson olefination reactions
作者:Sentaro Okamoto、Kousuke Tani、Fumie Sato、K. Barry Sharpless、Davit Zargarian
DOI:10.1016/s0040-4039(00)60454-9
日期:1993.4
Optically active, secondaryallylicalcohols can be prepared fromallylic silanes by the sucessive asymmetric dihydroxylation and Peterson olefination reactions. The Effects of trialkylsilyl groups on the outcome of the AD reaction on vinyl and allyl silanes are also discussed.