ABSTRACT
A general synthesis of optically active gamma-butyrolactone autoregulators is developed by a two-step sequence to assemble 2,3-trans-disubstituted butyrolactones in high yields and enantioselectivities; the scope of this reaction was elaborated by setting up a library of alkyl-substituted butyrolactones and the synthesis of the autoregulators IM-2 and VB-D.
Subject(s)
4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/chemistry , Streptomyces/chemistry , 4-Butyrolactone/chemical synthesis , Catalysis , StereoisomerismABSTRACT
Catalyst 5, an ion pair consisting of a hydrophilic cation and a lipophilic anion, fulfils the solubility requirements needed to couple efficiency (enantioselectivities and anti-diastereoselectivities up to > or = 99%) and catalyst recyclability in asymmetric aldol reactions under aqueous biphasic conditions.
Subject(s)
Aldehydes/chemistry , Water/chemistry , Acetates/chemistry , Catalysis , Hydrophobic and Hydrophilic Interactions , Imidazoles/chemistry , Proline/chemistryABSTRACT
Zinc-promoted hydroxyallylation of alpha-amidoalkyl arylsulfones 4 using 3-bromo-propenyl methyl carbonate 5 proceeds smoothly in DMF at room temperature to afford high yields of differentially protected anti-1,2-amino alcohols 6.
Subject(s)
Alkenes/chemical synthesis , Amino Alcohols/chemical synthesis , Catalysis , Gas Chromatography-Mass Spectrometry , Indicators and Reagents , Magnetic Resonance Spectroscopy , Stereoisomerism , Zinc/chemistryABSTRACT
[Structure: see text] [4R-[4alpha(S),5alpha]]-2,2-Dimethyl-4-(2-oxo-5-vinyl[1,3]dioxolan-4-yl)oxazolidine-3-carboxylic acid tert-butyl ester 5a, obtained in excellent yield and diastereoselectivity by the alpha-hydroxyallylation of the Garner aldehyde (4), is exploited in a novel high-yield synthesis of D-ribo-phytosphingosine (8), using microwave-enhanced cross metathesis as the key step in the chain elongation.
