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Synthesis of [ 2 H, 13 C]‐Labelled Diallylmalonates − Useful Probes for the Study of Transition Metal‐Catalysed 1,6‐Diene Cycloisomerisation
Author(s) -
Bray Katharine L.,
LloydJones Guy C.
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200105)2001:9<1635::aid-ejoc1635>3.0.co;2-c
Subject(s) - chemistry , allylic rearrangement , reagent , dimethyl fumarate , propargyl , electrophile , diene , organic chemistry , catalysis , psychology , psychiatry , multiple sclerosis , natural rubber
Reliable synthetic routes to isotopically labelled dimethyl [ 13 C, 2 H]diallylmalonates ( 1 ) have been developed. Dimethyl diallylmalonates readily undergo transition‐metal catalysed cycloisomerisation and the isotopically labelled substrates are expected to be of general utility in the study of the mechanism of such reactions. In the synthetic routes developed, the 2 H labelled allyl chains were introduced by reduction of propargyl functionality with Schwartz reagent. The regio‐ and stereo‐selectivity of such reactions allowing highly selective labelling strategies. The 13 C labelled allyl chains were introduced via Pd‐catalysed allylic alkylation of 13 C‐ or 2 H‐labelled dimethyl allylmalonate anions using [3‐ 13 C 1 ]allyl benzoate as the allylic electrophile. Using these methods, dimethyl [1,7‐( E,E )‐ 2 H 2 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 5 ), dimethyl [2,6‐ 2 H 2 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 6 ), dimethyl [1,7‐( Z,Z )‐ 2 H 2 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 7 ), dimethyl [1,1,2,6,7,7‐ 2 H 6 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 8 ), dimethyl [1,3‐ 13 C 1 ,5,7‐ 13 C 1 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 9 ), dimethyl [1,3‐ 13 C 1 ,6‐ 2 H 1 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 10 ), and dimethyl [1,3‐ 13 C 1 ,7‐( E )‐ 2 H 1 ]hept‐1,6‐dienyl‐4,4‐dicarboxylate ( 11 ) have been prepared.