72523-87-6

Upstream product

• 34713-70-7 2-Phenylpropanal 
• 72507-39-2 2,2-dimethyl-3-<(trimethylsilyl)oxy>-4-hexanone 
• 71821-69-7 1-(triethylsilyl)propan-1-one 
• 73198-94-4 2',6'-dimethylphenyl (2SR,3SR)-2,4-dimethyl-3-hydroxybenzenebutanoate 
• 80160-77-6 (2S,3S)-3,5-Dimethyl-2-((R)-1-phenyl-ethyl)-2,3-dihydro-pyran-4-one 
• 80160-78-7 (2S,3R)-3,5-Dimethyl-2-((R)-1-phenyl-ethyl)-2,3-dihydro-pyran-4-one 
• 116505-05-6 (5S,6R)-5-Methyl-6-((S)-1-phenyl-ethyl)-4-pyrrolidin-1-yl-5,6-dihydro-pyran-2-one 
• 77079-83-5 (3SR,5SR,6RS,7SR)-7-phenyl-6-hydroxy-2,2,5-trimethyl-3-<(trimethylsilyl)oxy>octan-4-one 
• 18245-72-2 S-phenylthiopropionate 

Downstream Products

• 72691-74-8 Methyl (2R^*,3S^*,4R^*)-3-hydroxy-2-methyl-4-phenylvalerate 
• 124508-31-2 (2R^*,3S^*,4S^*)-2-methyl-4-phenylpentane-1,3-diol 
• 40955-00-8 (2S,3S,4S)-2-Methyl-4-phenyl-pentane-1,3-diol 
• 124508-30-1 (2R^*,3S^*,4R^*)-2-methyl-4-phenylpentane-1,3-diol 
• 40955-00-8 (2R,3S,4S)-2-Methyl-4-phenyl-pentane-1,3-diol 

Relevant academic research and scientific papers

Acyl Silanes. Reagents for Diastereoselective Aldol Condensations

The acyl silanes 4a-c have been prepared and the stereochemistry of their aldol reactions with aldehydes have been investigated; the β-hydroxy ketones obtained were transformed into β-hydroxy acids by simple oxidation with basic hydrogen peroxide.

STEREOSELECTION IN THE REACTION OF ACID HALIDES AND VINYLOGOUS URETHANES

Acid halides which carry either an α-phenyl or α-alkoxy residue show fascinatingly high and useful diastereoselection on condensation with the vinylogous urethane derived ketene acetal enamine 3.Optically active halides or this type undergo reaction with

STEREOSELECTIVE ALDOL CONDENSATIONS VIA ALKENYLOXY DIALKYOXYBORANES: SYNTHETIC APPLICATIONS USING THIOESTERS.

A detailed investigation of the enolization of phenyl thiopropionate with ethylenechloroboronate (ECB) and diisopropylethylamine (DPEA) and the subsequent aldol condensations of these enolates was conducted.Alkenyloxy dialkoxyboranes derived from thioesters were found to be stereoconvergent: both Z and E enolates give syn aldol condensation products.The thioester additions to chiral aldehydes were studied.Internal selectivity (syn) was usually very high, while the relative stereoselectivity ranged from poor to good, depending on the specific aldehyde used.The aldol products were transformed to known compounds for correlation.

ACYCLIC STEREOSELECTION-13; ARYL ESTERS: REAGENTS FOR THREO-ALDOLIZATION

Preformed Li enolates of hindered aryl esters condense with aldehydes to give predominantly threo aldols.The method has been explored with esters 3 (DMP propionate), 4 (BHT propionate), 5 (DBHA propionate).DMP propionate reacts with benzaldehyde and α-unbranched aliphatic aldehydes to give threo:erythro ratios of about 6.5:1.However, with α-branched aliphatic aldehydes, ester 3 gives only threo-aldols.BHT propionate and DBHA propionate give only threo-aldols with all aldehydes studied.The DMP aldols may be converted into β-hydroxy acids by simple hydrolysis with KOH in aqueous methanol.BHT aldols cannot be hydrolyzed without retroaldolization.However, these aldols can be reduced to diastereomerically pure 1,3-diols.The DBHA aldols can converted into β-hydroxy acids by a method involving oxidation with ceric ammonium nitrate (CAN) in aqueous acetonitrile.Threo-selectivity is also seen in the condensations of DMP butyrate (15), DBHA butyrate (16), DMP pentenoate (17), and BHT pentenoate (18).The approach has been utilized in a stereoselective synthesis of racemic methyl corynomycolate.

Acyclic Stereoselection. 12. Double Stereodifferentiation with Mutual Kinetic Resolution. A Superior Class of Reagents for Control of Cram's Rule Stereoselection in Synthesis of erythro-α-Alkyl-β-hydroxy Carboxylic Acids from Chiral Aldehydes

Chiral α- ketones 7-9 have been prepared and their aldol condesations studied.Compound 8 shows from good to excellent inherent diastereoface selectivity in reactions with achiral aldehydes.Stereoselectivity is related to the size of the alkyl group attached to the aldehyde carbonyl; highest selectivity is observed with diphenylacetaldehyde (>10:1) and pivaldehyde (>19:1).Ketone 8 also shows high diastereoface selectivity in its reactions with chiral, racemic aldehydes 21, 25, 29, and 17, only one stereoisomeric aldol being obtained in each case.Furthermore, the four aforementioned aldehydes show much higher diastereoface selectivity with ketone 8 than they do with the related ketone 1.As a result, the reactions of racemic 8 with these chiral, racemic aldehydes show a high degree of "mutual kinetic resolution".In fact, the rate of the (R)-enolate plus (R)-aldehyde condensation is at least 35 times the rate of the (R)-enolate plus (S)-aldehyde condensation.It is shown by simple logical argument that such mutual kinetic resolution is expected in reactions between two chiral racemic compounds and that the magnitude of the effect should be proportional to the inherent diastereoselectivity shown by each compound in its reaction with achiral reaction partners.Thus, reagents such as 8 can be used to obtain the benefits of double stereodifferentiation even in the racemic form.As an application of the chemistry developed, (+/-)-blastmycinone (47) has been prepared in four steps from ketone 9 (20percent overall yield).