کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5229109 1383652 2008 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Investigations of the stereoselectivity of the intramolecular Diels-Alder reaction of a spiculoic acid model system
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Investigations of the stereoselectivity of the intramolecular Diels-Alder reaction of a spiculoic acid model system
چکیده انگلیسی

Model linear precursors to the spiculoic acids were prepared and underwent thermally induced IMDA reactions. The configuration of C5 in the stereotriad was found to dominate any inherent endo/exo selectivity of the IMDA reaction. The isomer (2E,5S)-20 underwent the IMDA to give the spiculoic acid stereochemistry in 84% yield and 94% ds. The required stereotriads were synthesised using stereoselective substrate-controlled aldol reactions; an anti-boron aldol reaction, controlled by the π-facial preference of (S)-2-benzoyloxypentan-3-one ((S)-27) led to (5R)-(22) and a syn-titanium aldol reaction, under the stereocontrol of a chiral N-acylthiazolidinethione (42) led to (5S)-(22). Chain extension using standard Wittig, HWE and 'modified' Julia olefinations installed the diene and dienophile components giving the linear precursors to the IMDA reactions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron - Volume 64, Issue 21, 19 May 2008, Pages 4852-4867
نویسندگان
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