A new and convenient method for converting olefins to aldehydes

The reaction of (E)-, (Z)-, or a 2:3 mixture of (E)- and (Z)-1,2-diphenyl-2-tolyl[2-14C]vinyl bromide ((E)-, (Z)-, or (E,Z)-3-Br-2-14C) in HOAc–AgOAc gave a 1:1 mixture of the structurally unrearranged but isotopically scrambled (E)- and (Z)-1,2-diphenyl-2-tolyl[1,2-14C]vinyl acetates ((E,Z)-3-OAc-1,2-14C), with an average of 18.3% scrambling of the 14C label from C-2 to C-1 arising from 1,2-tolyl shifts in the 1,2-diphenyl-2-tolylvinyl cation (3). No detectable amount of the structurally rearranged 2,2-diphenyl-1-tolylvinyl acetate (4-OAc) was formed. Solvolysis of (E,Z)-3-Br-2-14C in TFE-2,6-lutidine gave as products 62% 4-OTFE-1,2-14C and 38% of a 1:1 mixture of (E)- and (Z)-3-OTFE-1,214C. Only (Z)-3-OTFE-1,2-14C could be isolated as a pure product and it showed an average of 44.7% scrambling of the label from C-2 to C-1. Similar trifluoroethanolyses of (E,Z)-3-Br-2-13C coupled with gas chromatographic - mass spectral analyses of the diphenyl and phenyl tolyl ketones from ozonolysis of the product mixture showed 44.6% scrambling in the (E,Z)-3-OTFE-1,2-13C, confirming the 14C results for the (Z) isomer. Nondegenerate rearrangements from 1,2-phenyl shifts before and after the degenerate 1,2-tolyl shifts to give 4-OTFE-1-13C and 4-OTFE-2-13C were also observed, demonstrating the occurrence of successive 1,2-aryl shifts in these triarylvinyl cations.

Section: C/ (Ez)-3-otfe-2-13c and ~-Otfe-~-'~c/(ez)-~-otfe-mentioning

confidence: 99%

Solvolytic rearrangement studies with ¹⁴C or ¹³C labeled (E)- and (Z)-1,2-diphenyl-2-tolylvinyl bromides

Lee¹,

Wanigasekera²

1986

“…Ozonolysis of 9 in methanol at -78"C, followed by reaction with sodium borohydride at -40°C, gave exclusively the unstable hydroxyacrylate 20 (ir and nmr, only) which seemed to cyclize over a period of a few 1ioul.s to give 23, the structure of which was not rigorously established (Scheme 2). When the ozonolysis was carried out in methylene chloride and the ozonide reduced with dimethyl sulphide (13), tlie resultit~g aldehyde 10, mp 176-177"C, could be cleanly converted to tlie desired alcohol 11 by nieans of lithium aluminum tri-tert-butoxy hydride in d1.y T H F at 0°C. Attempts to convert 11 to its methyl ether 12 by nieans of methyl iodide -silver oxide (14) which was in accordance with what we expected.…”

mentioning

confidence: 99%

The synthesis of D,L-cis-N-oxalamido-3-N-phenylacetamido-4-methoxy methyl-2-azetidinone

Just¹,

Liak²

1978

“…methyl sulphide (25), afforded the crude a-ketoester 21. This was reacted directly with carbamoylmethylenetriphenylphosphorane (2) in chloroform, yielding maleimide 22 in 40% yield based on the a-methylene ester 20.…”

mentioning

confidence: 99%

C-Nucleosides and related compounds. XIV. The synthesis of a nitrogen analogue of showdomycin

Just¹,

Donnini²

1977