59983-36-7

Upstream product

• 59983-39-0 (S)-1-amino-2-(methoxymethyl)pyrrolidine 
• 96-22-0 pentan-3-one 

Downstream Products

• 157427-43-5 (3S,5R,6S,7R,8S)-8,9-Bis-benzyloxy-6-hydroxy-1-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-3,5,7-trimethyl-nonan-4-one 
• 175612-27-8 Benzoic acid (1S,2R,3S,4S)-3-(tert-butyl-dimethyl-silanyloxy)-1-((1S,2S)-2,3-dihydroxy-1-methyl-propyl)-6-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-2,4-dimethyl-hexyl ester 
• 157427-44-6 Benzoic acid (1S,2R,3S,4S)-1-((1R,2S)-2,3-bis-benzyloxy-1-methyl-propyl)-3-(tert-butyl-dimethyl-silanyloxy)-6-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-2,4-dimethyl-hexyl ester 
• 157427-39-9 (2S,3R,4R,5S,6S,7S)-1,2-Bis-benzyloxy-9-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-3,5,7-trimethyl-nonane-4,6-diol 
• 180592-99-8 (2S,3R,4S,5R,6S,7S)-1-(tert-Butyl-diphenyl-silanyloxy)-6-(2-methoxy-ethoxymethoxy)-9-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-3,5,7-trimethyl-nonane-2,4-diol 
• 175612-28-9 Benzoic acid (1R,2R,3S,4S)-3-(tert-butyl-dimethyl-silanyloxy)-1-[(R)-1-((S)-2,2-dioxo-2λ⁶-[1,3,2]dioxathiolan-4-yl)-ethyl]-6-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-2,4-dimethyl-hexyl ester 
• 180592-85-2 Benzoic acid (1R,2S,3S,4S)-1-((1R,2S)-2,3-bis-benzyloxy-1-methyl-propyl)-3-hydroxy-6-((2S,4R,6S)-4-methoxy-6-methyl-tetrahydro-pyran-2-yl)-2,4-dimethyl-hexyl ester 

Relevant academic research and scientific papers

Identification and assignment of the absolute configuration of biologically active methyl-branched ketones from limnephilid caddis flies

Glands of the 4th and 5th abdominal stemite of the caddis flies Potamophylax latipennis, Potamophylax cingulatus, and Glyphotaelius pellucidus contain (S)-4-methyl-3-heptanone (4a), (4S,6S)-4,6-dimethyl-3-octanone (4b), and (4S,6S)-4,6-dimethyl-3-nonanone (4c). As shown by gas chromatography coupled with electrophysiological recordings, these ketones elicit a strong response in the insects' antennae. The structural assignment of the compounds was achieved on the basis of mass spectra, enantioselective synthesis, and gas chromatography on a chiral stationary phase.

Diastereo- and enantioselective synthesis of syn-2,3-disubstituted 1,4-diketones via oxidative coupling of metalated hydrazones

An efficient diastereo- and enantioselective synthesis of syn-2,3-disubstituted 1,4-diketones 4 is described. Key step of the procedure is the oxidative coupling of the metalated SAMP/RAMP-hydrazones 2 with iodine, followed by oxidative cleavage of the dimerized bishydrazones 3 with ozone and subsequent separation of the minor meso-isomer by chromatography. The d,l-isomers of the title 1,4-diketones 4 are obtained in good overall yields (20-64%) and high diastereo- and enantiomeric excesses (de ≥ 98%, ee = 80 - ≥95%).

Asymmetric Synthesis of α′-Silylated α-Iodo Ketones via Iodination with Trifluoroiodomethane

The diastereo- and enantioselective syntheses of various α′-t-butyldimethylsilyl-α-iodo ketones 4a-h is described. The carbon iodine bond formation is achieved using trifluoroiodomethane as the electrophilic iodination reagent. The iodo ketones 4 are obtained in good yields and with excellent diastereo- and enantiomeric excesses (de,ee ≥ 98%).

Regio- and enantioselective synthesis of α-silyl aldehydes and ketones via SAMP/RAMP hydrazones

An efficient, highly regio- and enantioselective methodology for the synthesis of α-silyl aldehydes and ketones 2 and 6 using two different procedures was developed. Direct α-silylation of the azaenolates derived from SAMP/RAMP hydrazones 3 with various silyl trifluoromethanesulfonates resulted after oxidative removal of the chiral auxiliary in highly enantiomerically enriched α-silyl aldehydes and ketones (R)- or (S)-2. Alternatively, hydrazones 5 derived from acetaldehyde or methyl ketones were initially α-silylated followed by highly diastereoselective α-alkylation with suitable electrophiles. The latter variant allows the regiocontrolled synthesis of α-silyl ketones (S)-6 with high enantiomeric purity, not available by direct α-silylation of unsymmetrical ketone hydrazones. The absolute configuration of the resultant α-silyl carbonyl compounds 2 and 6 was derived from earlier mechanistic investigations of electrophilic substitutions via deprotonated SAMP/RAMP hydrazones and was unambiguously assigned by X-ray-crystallographical analysis of the α-silyl-SAMP hydrazone (S,R)-4c. VCH Verlagsgesellschaft mbH, 1996.

Total Synthesis of Swinholide A, Preswinholide A, and Hemiswinholide A

The total synthesis of swinholide A (1) has been accomplished via key intermediate aldehyde 12 (Fig. 3), whose construction started from L-rhamnose (18), epoxide 21, and phenylsulfone orthoester 22, and proceeded through an Enders asymmetric alkylation (16 + 17 -> 15), a Ghosez cyclization (21 + 22 -> 20), and a Corey-Sharpless coupling reaction (13 + 14 -> 12).Elaboration of compound 12 along slightly different pathways culminated in the synthesis of carboxylic acid 10 and hydroxy compound 11, whose union by an esterification reaction, followed by ring closure of the subsequently derived hydroxy acid under Yamaguchi conditions, led to swinholide A (1) upon deprotection.The chemistry developed also allowed the total synthesis of preswinholide A methyl ester (7), preswinholide A (8), and hemiswinholide A (78).Keywords: natural products; swinholide A; total syntheses

Regio-, Diastereo-, and Enantioselective Synthesis of vic-Diols via α-Silyl Ketones According to the SAMP/RAMP Hydrazone Method

α-Silylated ketones 5 or 10 of high enantiomeric purity (ee>=90percent) are easily available by silylation or silylation/alkylation of ketones 1 or 6, resp., according to the SAMP/RAMP hydrazone method.Reduction of 5 or 10 with L-selectride, followed by oxidative cleavage of the C-Si bond, leads to vic-diols 11-13 with high diastereoselectivity (de>=90percent) and without racemization.The stereoselectivity of the reduction depends on the structure of the α-silyl ketones 5 or 10, the reducing reagents, and the solvents used.Key Words: Ketones, α-silyl / vic-Diols, diastereo- and enantioselective synthesis / SAMP/RAMP Hydrazones / L-Selectride reductions

DIASTEREO- AND ENANTIOSELECTIVE SYNTHESIS OF α,α'-DISUBSTITUTED SPIROACETALS USING THE SAMP-/RAMP-HYDRAZONE METHOD

α,α'-Disubstituted spiroacetals were synthesized with excellent enantiomeric excesses and in good overal yields from symmetrical ketones employing the SAMP-/RAMP-hydrazone-method for asymmetric α,α'-alkylation.

ASYMMETRIC MICHAEL ADDITIONS VIA SAMP-/RAMP-HYDRAZONES ANTI-DIASTEREO- AND ENANTIOSELECTIVE SYNTHESIS OF 3,4-DISUBSTITUTED 5-OXO-ALKANOATES

An efficient and highly anti-diastereo-(de=90-100percent) and enantioselective (ee=92-100percent) synthesis of 3,4-disubstituted 5-oxo-alkanoates 3 in good overall chemical yields is described.The procedure involves the asymmetric Michael addition of aldehydes or ketones to enoates via their lithiated SAMP-/RAMP-hydrazones.Both enantiomers are accessible at will.