Allene Carboxylates as Dipolarophiles in Rh-Catalyzed Carbonyl Ylide Cycloadditions
作者:Laxmidhar Rout、Andrewâ M. Harned
DOI:10.1002/chem.200902208
日期:2009.12.7
Face‐to‐face: Allenecarboxylates can serve as efficient dipolarophiles for Rh‐catalyzed carbonylylidecycloadditions (see scheme). The endo and exo products arise from cycloaddition on the same face of the allene, but opposite faces of the dipole. This facial selectivity results in the formation of two of the four possible diastereomers.
Selectivity in the cycloadditions of carbonyl ylides with glyoxylates: an approach to the zaragozic acids—squalestatins
作者:David M. Hodgson、James M. Bailey、Carolina Villalonga-Barber、Michael G. B. Drew、Timothy Harrison
DOI:10.1039/b004870o
日期:——
Reaction of diazodiketoester 8 with glyoxylates in the presence of catalytic rhodium(II) acetate generates 6,8-dioxabicyclo[3.2.1]octanes 9 and 11 in good yield. Elaboration of 9 provides a suitable alcohol 25 for acid-catalysed rearrangement to give the 2,8-dioxabicyclo[3.2.1]octane skeleton 26 of the zaragozic acidsâsqualestatins. More substituted diazodiketoesters 36 and 40 also undergo highly regio- and diastereoselective cycloaddition with glyoxylates to give the cycloadducts 41, 43 and 44.
Reaction of carbonyl compounds with ethyl lithiodiazoacetate. Studies dealing with the rhodium(II)-catalyzed behavior of the resulting adducts
作者:Albert Padwa、Yashwant S. Kulkarni、Zhijia Zhang
DOI:10.1021/jo00300a035
日期:1990.6
A cycloaddition-rearrangement approach to the squalestatins
作者:David M. Hodgson、James M. Bailey、Timothy Harrison
DOI:10.1016/0040-4039(96)00893-3
日期:1996.6
Reaction of diazodiketoester 4 with methyl glyoxylate in toluene in the presence of catalytic rhodium(II) acetate generates the 6,8-dioxabicyclo[3.2.1]octane 5 as a single regio- and stereo-isomer in good yield. Elaboration provides a suitable alcohol 7 for acid-catalysed rearrangement to give the 2,8-dioxabicyclo[3.2.1]octane skeleton 8 of the squalestatins.