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1‐Halo‐1‐acceptor‐/1,1‐diacceptor‐substituted Allenes, 9. Functionalized Allenes, Haloallenes, and Bisallenes via [2,3]/[3,3]‐Sigmatropic Rearrangements and Their Reactivity
Author(s) -
Saalfrank Rolf W.,
Welch Andreas,
Haubner Martin,
Bauer Udo
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960205
Subject(s) - chemistry , ketene , allene , medicinal chemistry , yield (engineering) , sigmatropic reaction , elimination reaction , bromine , halogenation , thiophene , furan , organic chemistry , catalysis , materials science , metallurgy
Reaction of carbonyl compounds 1 with trimethylsilylacetylene 2 leads to the alkynols 3 , which are excellent precursors of acceptor‐substituted allenes. Compound 3 reacts with carbamoyl chloride 4 , diethyl chlorophosphate 6 , or hypohalite 8 to give the substituted alkynols 5, 7, 9 , Reaction of 9 with sulfinyl chloride 10 leads to the sulfinic esters 11 , which on heating undergo a [2,3]‐sigmatropic shift to yield the halosulfonyl allenes 12 . In the same manner the reaction of 7 and 9 with chlorophosphanes 13 or sulfenyl chlorides 15 gives rise to the generation of the phosphoryl allenes 14 and the haloallenyl sulfoxides 16 , respectively. Alkynyl ketene acetal intermediates 18 are formed by starting from the alkynols 9 and orthoesters 17 . Spontaneous [3,3]‐sigmatropic rearrangement of 18 gives the haloallenyl esters 19 . Reaction of alkynols 5 with sulfur dichloride leads to the alkynylsulfinyl esters 20 , which on heating rearrange to the bisallenyl sulfones 21 . Pyrolysis of 21 yields the thiophene 1,1‐dioxides 22 . Bisphosphorylbisallene 24 is synthesized from hexadiyndiol 23 by reaction with chlorodiethoxyphosphite. Halophosphoryl allenes 14 react with bromine to yield the oxaphospholenes 25 by cyclization and subsequent elimination of ethanol, or oxaphospholenes 26 , if no appropriate leaving group is present in the molecule. Sulfonyl‐1,3‐dienes 27 can be synthesized by reaction of halosulfonylallenes 12 with bromine, followed by elimination of HBr. Haloallenyl ester 19a is converted in a non‐generalizable reaction with bromine into the tribromo‐3 6‐dihydro‐2‐pyranone 30 .

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