Flexible Synthesis of Pyrimidines with Chiral Monofluorinated and Difluoromethyl Side Chains
摘要:
Chiral pyrimidines with a fluorine atom in the benzylic position are easily accessible in high enantiomeric excesses from optically active propargylic intermediates by two complementary routes. Both the use of optically active propargylic fluorides and the fluorination of the chiral pyrimidine in the final stage give excellent results in terms of enantiocontrol. On the other hand, original pyrimidines with a difluoromethyl side chain are also obtained in a few steps from new propargylic ketones bearing a CHF2 substituent on the triple bond.
Chiral pyrimidines with a fluorine atom in the benzylic position are easily accessible in high enantiomeric excesses from optically active propargylic intermediates by two complementary routes. Both the use of optically active propargylic fluorides and the fluorination of the chiral pyrimidine in the final stage give excellent results in terms of enantiocontrol. On the other hand, original pyrimidines with a difluoromethyl side chain are also obtained in a few steps from new propargylic ketones bearing a CHF2 substituent on the triple bond.
Irreversible<i>endo</i>-Selective Diels-Alder Reactions of Substituted Alkoxyfurans: A General Synthesis of<i>endo</i>-Cantharimides
作者:Robert W. Foster、Laure Benhamou、Michael J. Porter、Dejan-Krešimir Bučar、Helen C. Hailes、Christopher J. Tame、Tom D. Sheppard
DOI:10.1002/chem.201406286
日期:2015.4.13
The [4+2] cycloaddition of 3‐alkoxyfurans with N‐substituted maleimides provides the first general route for preparing endo‐cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2‐substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising