Showing papers on "Dichlorophenylphosphine published in 1992"

Reactions of 1,2-oxaphospholenes. 7. Anomalous low reactivity of a tertiary allylic bromide. The crystal and molecular structure of (E)-4,5-dibromo-3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide

Abstract: Reaction of 2,2,6,6-tetramethgl-4-heptyn-9-ol (5) with dichlorophenylphosphine leads to (2,2,6,-tetramethyl-3,4 heptadien-3-yl)phenylphosphinic acid (7), which undergoes Ag + -catalysed cyclization to 3,5-di-tert- butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide (1e, 75-55% Z, 25-45%E). Electrophilic bromination of 7 affords 1f, the 4-bromo derivative of 1e, as a 75% Z 55% E diastereomer mixture from which pure (Z)-1f can be isolated. Free radical allylic bromination of 1e and 1f leads to the corresponding 5-bromo derivatives 2e and 2f, each as the single diastereoisomer

Production of phosphine compound, its intermediate and production thereof

Abstract: PURPOSE:To obtain the title optically pure compound useful for asymmetric syntheses as a ligand of catalyst by reacting dichlorophenylphosphine with a Grignard reagent, and reacting the prepared diastereomer mixture, etc., with a lithium compound, etc. CONSTITUTION:For example, a compound shown by formula I (Ph is phenyl) is allowed to react with a Grignard reagent shown by formula II (X is halogen) preferably in an argon atmosphere, then reacted with (-)-menthol, further reacted with borane-THF complex to give a diastereomer mixture shown by formula III, which is directly subjected to react with a compound shown by formula IV or separated and reacted with the compound of formula IV to give a compound present as an enantiomer shown in formula V. The compound shown by formula V is allowed to react with an alkyllithium shown by the formula R-Li (R is lower alkyl) in the presence of copper chloride to give a compound as an enantiomer shown in formula VI and further reacted with a base to give the objective compound as an enantiomer shown in formula VII.