Allenyl phosphonates

Regio- and stereoselective cyclization-Heck reaction of monoesters of 1,2-allenyl phosphonic acids with alkenes afforded 4-(1 (Z)-alkenyl)-2-ethoxy-2,5-dihydro-1,2-oxaphosphole 2-oxides (eq 115). ... 

Other Studies. - The P NMR chemical shifts of alcohols, carboxylic acids and phenols phosphitylated with 2-chloro-4,4,5,5-tetramethyl-dioxaphospholane have been correlated with substituent effects of phenols. P NMR spectroscopy has also been used to study activation pathways of aryl H-phosphonate ester condensation reactions, the conversion of allenyl and divinyl phosphines to 1- and 2-phosphadienes, the reaction of tetraphosphorus decasulfide with dialkyl disulfides, the reaction of phosphine with cyclic olefins, the chemical shift tensors of powder samples of phosphole derivatives, the reactions of alcohols and mercaptans with tetraphosphorus trichalcogen diiodides, the structure of aminomethanebisphosphonic acids, and reactions of 00-di-(2-ethylhexyl)dithiophosphoric acids. ... 

Toste has developed an alternative approach to the enantioselective hydroamina-tion of N-allenyl sulfonamides that employs a chiral or achiral gold complex in combination with a chiral phosphonate anion [43]. As an example of this approach, treatment ofy-allenyl sulfonamide 63 with a catalytic 1 1 mixture of the achiral mono (gold) phosphine complex (PMe2Ph)AuCl and chiral, enantiomerically pure silver phosphonate Ag-( J )-64 (5 mol%) in benzene at room temperature for 48 h formed 2-alkenyl pyrrolidine 65 in 84% isolated yield with 99% ee (Eq. (11.36)). 

Toste has demonstrated the hydroalkoxycarbonylation of P-allenyl carboxylic acid derivatives catalyzed by a mixture of a chiral, enantiomerically pure bis(gold) complex and a chiral, enantiomerically enriched silver phosphonate salt [107]. As an example, treatment of 6-methyl-4,5-heptadienoic acid with a catalytic mixture of [(S)-binapj (AuC1)2 and Ag-(J )-67 formed the yluctone 83 in 88% yield with 82% ee (Eq. (12.43)) [107]. 

Hydroformylation of allenes (1,2-butadienes) was mentioned only once in the literature. Fell and Beutler [91] reacted allenes with syngas in the presence of HRh(CO)(PPh3)3 but obtained only a mixture of mono- and dialdehydes. In 2008, Guo and Ma [92] used 1,2-allenyl phosphine oxides and phosphonates as substrates and, under the control of the same catalyst, achieved exclusively the production of the terminal aldehydes. 

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