A convenient route to aryl substituted chloro and bromo olefins
作者:Sudha Kumaraswamy、K.C.Kumara Swamy
DOI:10.1016/s0040-4039(97)00277-3
日期:1997.3
A wide range of aryl substitutedchloro and bromo olefins has been prepared by treating α-chloro and α-bromophosphonates derived from 1-hydrido-5,5-dimethyl-1,3,2-dioxaphosphorinane with sodium hydride in THF at 0°C followed by an aldehyde.
reaction of inexpensive α-chlorophosphonates with alkyl acrylates in the presence of sodium hydride is reported. Reaction with dimethylmaleate or fumarate also leads to cyclopropyl-substituted phosphonates. These reactions take place via Michaeladdition of acrylate, dimethylmaleate, or fumarate to the phosphonate carbanion, followed by expulsion of the chloride ion.
Chlorophosphonates: Inexpensive Precursors for Stereodefined Chloro-Substituted Olefins and Unsymmetrical Disubstituted Acetylenes
作者:C. Muthiah、K. Praveen Kumar、C. Aruna Mani、K. C. Kumara Swamy
DOI:10.1021/jo991946y
日期:2000.6.1
New chlorophosphonates bearing a 1,3,2-dioxaphosphorinane ring which are useful for the stereospecific synthesis of 5-chlorofurfuryl substituted olefins and chloro-substituted dienes have been obtained by an easy, inexpensive route. The utility of some of these in the synthesis of ferrocenyl- and anthracenyl-substituted unsymmetrical acetylenes has been explored. The structures of the phosphonates (OCH2CMe2CH2O)P(O)CH2(C4H2ClO) (4) and (OCH2Me2CH2O)P(O)-(CH=CHCH(Cl)Ph (7) have been determined; in addition, the stereochemistry of (5-chlorofurfuryl)-CH=CH(4-ClC6H4) (13b) and 2,4-Cl2C6H3-CH=CH-CH=C(Ph)Cl (14a) is unambiguously proved by the X-ray structure determination.