Asymmetric Bromolactonization Using Amino-thiocarbamate Catalyst
摘要:
A novel amino-thiocarbamate-catalyzed bromolactonization of unsaturated carboxylic acids has been developed. The scope of the reaction is evidenced by 22 examples of gamma-lactones with up to 99% yield and 93% ee. The protocol was applied in the enantioselective synthesis of the key intermediates of VLA-4 antagonists.
The synthesis of novel, highly functionalized, C 2-symmetric sulfur-based catalysts is developed and their catalytic applications are explored in asymmetric bromo-, iodo- and seleno-functionalizations of alkenoicacids. This protocol provides the corresponding normal- and medium-sized bromo, iodo and selenolactones in up to 98% yield and 83% stereoselectivity.
开发了新型、高度官能化的 C 2 对称硫基催化剂的合成,并探索了它们在烯酸的不对称溴、碘和硒官能化中的催化应用。该方案以高达 98% 的产率和 83% 的立体选择性提供相应的正常和中等大小的溴、碘和硒内酯。
作者:Daniel H. Paull、Chao Fang、James R. Donald、Andrew D. Pansick、Stephen F. Martin
DOI:10.1021/ja305117m
日期:2012.7.11
highly enantioselectivebromolactonizations of a number of structurally distinct unsaturated acids. Like some known catalysts, this catalyst promotes highly enantioselectivebromolactonizations of 4- and 5-aryl-4-pentenoic acids, but it also catalyzes the highly enantioselectivebromolactonizations of 5-alkyl-4(Z)-pentenoic acids. These reactions represent the first catalytic bromolactonizations of alkyl-substituted
Enantioselective Halolactonization Reactions using BINOL-Derived Bifunctional Catalysts: Methodology, Diversification, and Applications
作者:Daniel W. Klosowski、J. Caleb Hethcox、Daniel H. Paull、Chao Fang、James R. Donald、Christopher R. Shugrue、Andrew D. Pansick、Stephen F. Martin
DOI:10.1021/acs.joc.8b00490
日期:2018.6.1
A general protocol is described for inducing enantioselective halolactonizations of unsaturated carboxylic acidsusing novel bifunctional organic catalysts derived from a chiral binaphthalene scaffold. Bromo- and iodolactonization reactions of diversely substituted, unsaturated carboxylic acids proceed with high degrees of enantioselectivity, regioselectivity, and diastereoselectivity. Notably, these
A facile and efficient enantioselectivebromoaminocyclization of unsaturated sulfonamides has been developed using an amino-thiocarbamate catalyst. A range of enantioenriched pyrrolidines were prepared with up to 99% yield and 99% ee. The corresponding lactams could be obtained through oxidation of the pyrrolidines.
The apple never falls far from the tree: S‐alkylthiocarbamate 1 (see scheme, NBP=N‐bromophthalimide) was prepared in high yield through a synthetic sequence involving a Newman–Kwart rearrangement of the corresponding O‐alkylthiocarbamates. Compound 1 was used to catalyze bromolactonization, thus providing enantioenriched δ‐lactones in excellent yield and enantioselectivity.