Asymmetric alkylations of n-acyl dihydropyrimidinones
摘要:
Enantiomerically pure dihydropyrimidin-4-one 1 has been employed as a chiral auxiliary for enantioselective alkylation reactions. Acylation of 1, followed by enolate formation, alkylation and acyl cleavage, affords alpha-alkylated carboxylic acids in high chemical yield and enantiomeric purity.
Conformational Preference in Bis(porphyrin) Tweezer Complexes: A Versatile Chirality Sensor for α-Chiral Carboxylic Acids
作者:Marina Tanasova、Babak Borhan
DOI:10.1002/ejoc.201200147
日期:2012.6
determinant of binding conformation. Experimental results indicate that a balance between linker flexibility and rigidity could yield an optimum porphyrintweezer that stabilizes a common conformation for all bound chiral guests. This leads to a more simplified approach to absolute stereochemical determination of asymmetry for small organic molecules. This was demonstrated by the use of a C3-linked zincated
Stereoselective allylation of aldehydes on solid support and its application in biology-oriented synthesis (BIOS)
作者:Victor Mamane、Ana B. García、Jayant D. Umarye、Torben Lessmann、Stefan Sommer、Herbert Waldmann
DOI:10.1016/j.tet.2007.01.041
日期:2007.6
allylation of aldehydes on solid support is reported. Different kinds of chiral allylboron reagents with complementary direction of stereoinduction were applied successfully in this reagent-controlled transformation. The homoallylic alcohol products are generated with high levels of stereoselectivity and in high yields. The crotylation of aldehydes on solid support employing (E)- and (Z)-Ipc2crotylborane
Total synthesis of (−)-eburnamonine and (+)-epi-eburnamonine from a chiral non-racemic 4,4-disubstituted γ-lactone
作者:Andrew G.H Wee、Qing Yu
DOI:10.1016/s0040-4039(99)02131-0
日期:2000.1
The total synthesis of (−)-eburnamonine and (+)-epi-eburnamonine was successfully achieved using a key chiral non-racemic 4,4-disubstituted γ-lactone 4 that was prepared via the Rh(II) carbenoid mediated tertiary C–H insertion reaction of a chiral non-racemic diazomalonate 5.