Ferrocenyl substituted chlorostilbenes and butadienes

The readily accessible α-chlorophosphonates (OCH2CMe2CH2O)P(O)CH(Cl)---C6H4-4-R [1: R=Me (a), OMe (b), Cl (c), H (d)] react with ferrocenecarboxaldehyde in the presence of NaH [Horner-Wadsworth-Emmons reaction] to give good yields of ferrocenyl substituted chlorostilbenes. The novel bis ferrocenyl butadiene C5H5FeC5H4---CH=CH---C(CN)CHC5H4FeC5H5 (9) as well as the ferrocenyl 2-cyano-1,3-butadienes 4-R---C6H4---CH=CH---C(CN)=CHC5H4FeC5H5 [R=Me (10a), OMe (10b), Cl (10c)] have been obtained by using the new allylphosphonate (OCH2CMe2CH2O)P(O)CH2C(CN)=CHC5H4FeC5H5 (8); the latter compound was prepared in good yields by the reaction of the Baylis-Hillman adduct, C5H5FeC5H4CH(OH)C(CN)=CH2 (7), with the chlorophosphite (OCH2CMe2CH2O)PCl. The electrochemical behavior of the ferrocenyl compounds thus synthesized has been studied; two reversible one-electron processes are observed in the case of compound 9 suggesting a cooperative interaction between the two ferrocenyl residues

A convenient chromatography-free access to enantiopure 6,6'-di-tert-butyl-1,1'-binaphthalene-2,2'-diol and its 3,3'-dibromo, di-tert-butyl and phosphorus derivatives: utility in asymmetric synthesis

A simple chromatography-free high-yielding synthesis of the hexane-soluble enantiopure 6,6'-di-tert-butyl-1,1'-binaphthalene-2,2'-diol 3 (6,6'-di-tert-butyl BINOL) using Friedel-Crafts reaction on 1,1'-binaphthalene-2,2'-diol 1 (BINOL) is described. The enantiomeric purity was fully maintained in the reaction. Compound 3 has been used as an entry point for the convenient chromatography-free synthesis of 3,3',6,6'-tetra-tert-butyl BINOL 4 and 3,3'-dibromo-6,6'-di-tert-butyl BINOL 5. A straightforward route to enantiopure bisphosphites [(6,6'-R2C20H10O2)P]2[O2C20H10-6,6'-R2] [R = H 15, t-Bu 16] by simply reacting phosphorochloridite (6,6'-R2C20H10O2)PCl [R = H20, t-Bu 6] with metallic sodium is highlighted. The identity of 15 and 16 as their selenium-oxidized products 17 and 18 (at phosphorus center) is confirmed by X-ray crystallography (17 in the enantiopure form and 18 as racemate). Various enantiopure phosphoramidites of the modified BINOL have been synthesized. It is established that even when the phosphoramidites derived from the unsusbstituted BINOL 1 fail to give an appreciable optical induction in the asymmetric reduction of acetophenone/phenacyl chloride, those derived from 3 do induce moderate chiral induction (up to 30% ee in the case for acetophenone and 43% ee in the case of phenacyl chloride), thus leaving scope for further improvement in ee for related reactions

The first structural study on a cyclic tricoordinate phosphorochloridite and a pentacoordinate phosphorane based on 1,2,3,5-protected myo-inositol-a new conformation of 1,3,2-dioxaphosphorinane ring

Treatment of the phosphoramidite {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2P-NH-i-Pr)} with o-chloranil affords the first example of inositol-based pentacoordinate phosphorane {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2P-NH-i-Pr)(1,2-O2C6Cl4)} (9) (X-ray structure) with a trigonal bipyramidal geometry at phosphorus. The six-membered 1,3,2-dioxaphosphorinane ring with the inositol residue has an unusual boat conformation in 9 which is quite different from that found in unrestrained rings investigated before, but is similar to that of its PIII chloro precursor {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2PCl)} (X-ray structure). Also, a convenient and chromatography-free procedure for the protected myo-inositol derivative {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(OH)2} is reported

Chemistry and Toxicology of Sulphur Mustard- A Review

Bis (2-chloroethyl) sulphide commonly known as sulphur mustard (SM) is highly reactive bifunctional compound, documented as antimitotic, mutagenic, carcinogenic, teratogenic and cytotoxic agent. It is a powerful vesicant and has been employed as a chemical warfare agent. Skin, eyes and respiratory tract are the principal target organs and the deoxyribose nucleic acid (DNA) is the most important molecular target of SM toxicity. There is no specific antidote for SM injury .Treatment to SM toxicity is symptomatic

Hydrophosphonylation of activated alkenes and alkynes via fluoride ion activation in ionic liquid medium

A simple transition metal-free hydro/hydrothiophosphonylation of Baylis-Hillman adducts, substituted allyl bromides, allenylphosphonates and alkynes, promoted by fluoride ion in ionic liquid, is described. Clear-cut evidence for fluoride activation of the phosphite via pentacoordinate phosphorus is provided for the first time. Also, in a comparative reaction, the product obtained was different from that from the palladium catalyzed one. Structures of key products are proven by X-ray crystallography

Allylation of p-ketoaldehydes and functionalized imines by diallyltin dibromide: formation of skipped and conjugated dienes

Diallyltin dibromide reacts with β-keto-aldehydes possessing no aromatic side groups and with (hydroxy) aryl imines to afford the expected homoallyl alcohols or amines respectively. With β-ketoaldehydes having aromatic side groups, skipped or conjugated dienes are obtained depending on whether or not an aqueous work up procedure is used

Cyclic chlorophosphites as scaffolds for the one-pot synthesis of α-aminophosphonates under solvent-free conditions

New α-aminophosphonates of the type (OCH2CMe2CH2O)P(O)CH(NHCO2R)(R') [6a-i, 7a-e, and 8a-c] have been synthesized in high yields by a three-component reaction using (OCH2CMe2CH2O)PCl (3), benzamide (or urethane or benzyl carbamate), and an aldehyde without using any catalyst under solvent-free conditions. This route can be readily adapted for bis-aminophosphonates as well as optically active binaphthoxy α-aminophosphonates; it also tolerates the phenolic -OH group as shown by the synthesis of hydroxy functionalized aminophosphonates. Partial hydrolysis of compounds 7a-d leads to products in which the phosphorinane ring is cleaved first. Compounds (OCH2CMe2CH2O)P(O)CH[NHC(O)Ph](9-anthryl) (6f) and optically pure (R,S)-(-)-(C20H12O2)P(O)CH(NHCO2Et)(Ph) (14a) were characterized by X-ray crystallography

Characterization of the first hexacoordinate phosphorus compound with S→P←S bonds

The first example of a hexacoordinate phosphorus compound [S{6-t-Bu-4-Me-C6H2O}2]2P+(Cl-· C3H4N2) with two S→P bonds is reported. This compound can be construed as an oxophosphonium salt with double intramolecular coordination by sulfur atoms. X-ray structure reveals a facial arrangement of the ligands with two coordinating sulfur atoms cis to each other. The S→P distance of 2.334 (1) Å is one among very short coordinate bond distances between sulfur and phosphorus