65203-03-4

Upstream product

• 1117-71-1 methyl-4-bromo-2-butenoate 
• 100-52-7 benzaldehyde 
• 186581-53-3 diazomethane 
• 69637-13-4 2-[hydroxy(phenyl)methyl]but-3-enoic acid 
• 3724-55-8 methyl but-3-enoate 
• 1117-71-1 methyl 4-bromocrotonate 
• 3724-65-0 2-butenoic acid 

Downstream Products

• 154073-05-9 methyl 2-phenyl-2,5-dihydro-3-furancarboxylate 

Relevant academic research and scientific papers

Synthesis of α-alkenyl-β-hydroxy adducts by α-addition of unprotected 4-bromocrotonic acid and amides with aldehydes and ketones by chromium(II)-mediated reactions

The regioselective and diastereoselective chromium(II)-mediated reactions of 4-bromocrotonic acid or amides with aldehydes and ketones can proceed without the need to protect protic sites to generate the respective α-alkenyl-β-hydroxy adducts, i.e. formally the addition of the α-anion of a carboxylic acid or amide to an oxo-compound is featured.

Total regio- and diastereocontrol in the aldol reactions of dienolborinates

It is reported that appropriate dienolborinates can provide access to both diastereomers of 2-(hydroxymethyl)but-3-enoates through exclusive α-regiocontrol in a non-vinylogous pathway. Contrary to previous reports in which dialkylchloroboranes failed to enolize propanoates, acidity-enhanced but-3-enoates readily undergo enolization, offering unprecedented control over the formation of these valuable synthons. The first example of an aldol reaction in the presence of a phosphine-borane adduct is also reported.

An efficient approach to (E)-β-methyl Baylis-Hillman adducts via indium-mediated allylation of aldehydes in aqueous media

A new method has been developed for the synthesis of (E)-β-methyl Baylis-Hillman adducts with high E-Z (>93%) selectivity in modest to good yields. The process consists of two steps: an indium-mediated allylation reaction and a simple base-catalyzed isomerization step. Various aldehydes were allylated with allyl bromides using indium under very mild conditions in aqueous media. The allylation reactions of aromatic and aliphatic aldehydes were largely accelerated by the presence of HCl.

Catalytic oxyselenenylation-deselenenylation reactions of alkenes - Stereoselective one-pot conversion of 3-alkenols into 2,5-dihydrofurans

A stereoselective multi-step one-pot procedure for converting 2- methoxycarbonyl-3-alkenols into 3-methoxycarbonyl-2,5-dihydrofurans, using only catalytic amounts of diphenyl diselenide and an excess of ammonium persulfate, has been developed. The erythro alkenols give the trans dihydrofurans, while the threo stereoisomers give the corresponding cis products. The configurations of the starting alkenols were deduced from those of the intermediate phenylseleno tetrahydrofurans, which were independently obtained from reactions of the alkenols with stoichiometric amounts of phenylselenenyl sulfate.

Dienediolates from Unsaturated Carboxylic Acids. Reaction with para-Substituted Benzaldehydes. Electronic Effects on Regioselectivity

Regioselectivity α/γ ratios for addition of the lithium dienediolate of crotonic acid to para-substituted benzaldehydes are subject to small electronic effects when reactions are carried out at low temperature, but strong influence by substituents is observed on heating for 1 h at 60 deg C.A linear correlation is then found between regiochemical ratios and ?p parameters.Stereoselectivity RR/RS ratios (33:66 to 43:57) for α-adducts obtained in the cold do not depend on the substituents.

REFORMATSKY TYPE REACTION WITH NEW ALUMINIUM REAGENTS CONTAINING Al-Sn OR Al-Pb LINKAGE.

Treatment of alpha -bromo carbonyl compounds with the reagent prepared from n-Bu//3SnLi and Et//2AlCl or from SnCl//2 and Et//2AlCl affords enolates which react with ketone or aldehyde to give beta -hydroxy carbonyl compounds in good to excellent yields. The reactions proceed similarly with the reagents which are generated from R//3PbLi (R equals Ph, n-Bu) and Et//2AlCl. Catalysis by the added Pd(PPh//3)//4 complex promotes the reduction effectively and improves the yields of the desired adducts. The regio- and stereoselectivities are disclosed.

A NEW METHOD FOR THE SYNTHESIS OF β-HYDROXYESTERS BY USING METALLIC TIN

Metallic tin or activated metallic tin, prepared by reduction of stannous chloride with lithium aluminum hydride, smoothly reacts with α-haloesters to yield tin enolates, which in turn react with carbonyl compounds under mild conditions to give, after hydrolysis, β-hydroxyesters in high yields.

A New and Highly Effectiwe Aldol Synthesis

A new approach has been demonstrated for the regiospecific aldol synthesis by the simultaneous addition of α-halo carbonyl derivatives and aldehydes or ketones to a suspension of diethylaluminium chloride and zinc in tetrahydrofuran at low temperature.This technique is also employable under mild conditions for the Reformatsky reaction to give β-hydroxy esters in excellent yield.One of the unique synthetic applications of this process is illustrated by the intramolecular cyclization of α-bromo esters of ω-hydroxy aldehyde,which produces macrolides, an important cla ss of compounds in the antibiotic field.