55848-85-6

Upstream product

• 674-82-8 4-methyleneoxetan-2-one 
• 104-53-0 3-phenyl-propionaldehyde 
• 67-56-1 methanol 
• 105-45-3 acetoacetic acid methyl ester 

Downstream Products

• 107400-61-3 (3R^*,5R^*)-Methyl 3,5-Dihydroxy-7-phenylheptanoate 
• 86031-05-2 (4R,6R)-6-(2-cyclohexylethyl)-4-hydroxytetrahydropyran-2-one 
• 202662-31-5 5-(tert-Butyl-dimethyl-silanyloxy)-2-diazo-3-oxo-7-phenyl-heptanoic acid methyl ester 
• 202662-29-1 5-(tert-Butyl-dimethyl-silanyloxy)-3-oxo-7-phenyl-heptanoic acid methyl ester 

Relevant academic research and scientific papers

Dirhodium(II)-catalysed intramolecular carbon-hydrogen insertion reaction of α-diazo ketones: Stereoselective synthesis of 2,3-cis-2-alkyl-5-oxo-3-silyloxycyclopentanecarboxylates

Methyl 5-(tert-butyldimethylsilyloxy)-2-diazo-3-oxoheptanoate 2a, upon treatment with 1 mol% of dirhodium(II) tetraacetate in dichloromethane under reflux, gives a mixture of methyl (1R*,2R*,3S*)-3-(tert-butyldimethylsilyloxy)-2-methyl-5- oxocyclopentanecarboxylate 3a and its (1S*,2S*,3S*) isomer 4a in a ratio of 79:21 and 87% combined yield. Similarly, 5-(tert-butyldimethylsilyloxy)-2-diazo-3-oxoalkanoates 2c-g give 2,3-cis-2-alkyl- (or 2-phenyl)-3-(tert-butyldimethylsilyloxy)cyclopentanecarboxylates 3c-g as the major products. The presence of both the keto and ester groups in the precursors was found to be essential for this site- and stereo-selective C-H insertion to take place. A possible interpretation for the observed stereoselectivity is presented.

Diastereoselective Synthesis of Protected Syn 1,3-Diols by Base-Catalyzed Intramolecular Conjugate Addition of Hemiacetal-Derived Alkoxide Nucleophiles

Reaction of the illustrated unsaturated hydroxy esters (X = OMe, R2 = H, Me) and amides (X = N(Me)OMe, R2 = H, Me) with benzaldehyde and potassium alkoxide or amide bases is reported.The resulting benzylidene acetals are obtained in