A new chiral titanium species for the ring opening reactions of meso epoxides
摘要:
The synthesis of a new chiral ligand 1 based on the conformationally defined 1,7-dioxaspiro[5.5]undecane ring system is reported. Generation of the corresponding ligand 1-Ti(OiPr)(4) complex as a catalyst and its use in the enantioselective ring opening reaction of cyclohexene oxide with TMSN3 is described. (C) 1997 Elsevier Science Ltd.
Regioselective Alkyl and Alkynyl Substitution Reactions of Epoxy Alcohols by the Use of Organoaluminum Ate Complexes: Regiochemical Reversal of Nucleophilic Substitution Reactions
作者:Minoru Sasaki、Keiji Tanino、Masaaki Miyashita
DOI:10.1021/ol010062+
日期:2001.5.1
Unprecedented nucleophilic substitution reactions of 2,3-epoxy-1-alkanols with alkyl and alkynylaluminum ate complexes have been studied and demonstrated to occur at the C2 position with extremely high stereoselectivity, i.e., with exactly reversed regioselectivity to that obtained in the substitution reactions by normal organoaluminum reagents, resulting in the formation of the C2-alkyl and C2-alkynyl substitution products in excellent yields.
A new chiral titanium species for the ring opening reactions of meso epoxides
作者:Alecia W. Eppley、Nancy I. Totah
DOI:10.1016/s0040-4020(97)01035-1
日期:1997.12
The synthesis of a new chiral ligand 1 based on the conformationally defined 1,7-dioxaspiro[5.5]undecane ring system is reported. Generation of the corresponding ligand 1-Ti(OiPr)(4) complex as a catalyst and its use in the enantioselective ring opening reaction of cyclohexene oxide with TMSN3 is described. (C) 1997 Elsevier Science Ltd.
Total Synthesis of Callyspongiolide, Part 2: The Ynoate Metathesis/
<i>cis</i>
‐Reduction Strategy
作者:Bernhard Wölfl、Guillaume Mata、Alois Fürstner
DOI:10.1002/chem.201804988
日期:2019.1.2
The macrocyclic core of the cytotoxic marine natural product callyspongiolide (1) was forged by ring‐closing alkyne metathesis (RCAM) of an ynoate precursorusing a molybdenum alkylidyne complex endowed with triarylsilanolate ligands as the catalyst. This result is remarkable in view of the failed attempts documented in the literature at converting electron deficient alkynes with the aid of more classical