Premium
Diastereoselective Access to 3‐Nitro‐4‐vinylidenetetrahydrofurans and 3‐Nitro‐4‐vinylidenetetrahydropyrans and Their Conversion into 3,6‐Dihydro‐1,2‐oxazines by Reverse Cope Elimination of Hydroxylamine Precursors
Author(s) -
Dumez Estelle,
Faure Robert,
Dulcère JeanPierre
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(200107)2001:13<2577::aid-ejoc2577>3.0.co;2-b
Subject(s) - chemistry , nitro , hydroxylamine , oxazines , sn2 reaction , alcohol , allylic rearrangement , medicinal chemistry , organic chemistry , catalysis , alkyl
A new approach to the synthesis of unsaturated nitro‐allenyl‐tetrahydrofurans 3 and ‐tetrahydropyrans 5 has been developed, involving oxa‐Michael addition/S N 2′ substitution of propargyl and homopropargyl alcohol derivatives 2a and 4h on nitroalkenes 1a − g . Complete allylic 1,3‐strain control during the cyclization accounts for the observed diastereoselectivity. Reduction of nitro compounds 3 and 5 with SmI 2 provided new α−allenylhydroxylamines 7 and 8 , which were easily isomerized into 3,6‐dihydro‐1,2‐oxazines 9 and 10 by reverse Cope elimination.