An efficient synthesis of both enantiomers of trans-1,2-cyclopentanediol and their conversion to two novel bidentate phosphite and fluorophosphinite ligands
polysubstituted tetrahydrofurans. 1,4-Diols and their derivatives can be rapidly cyclized to furnish tetrahydrofurans in high yields with one equivalent of Ph3P/NBS. Higher amount of Ph3P/NBS leads to the formation of dibromobutanes. A triphenylphosphine–N-bromosuccinimide mediated chemoselective cyclodehydration of diols is presented for the synthesis of polysubstituted tetrahydrofurans. 1,4-Diols and their
摘要 三苯基膦-N-溴代琥珀酰亚胺介导的二醇的化学选择性环脱水用于合成多取代的四氢呋喃。1,4-二元醇及其衍生物可以快速环化,以高产率提供一当量的Ph 3 P / NBS。较高的Ph 3 P / NBS含量导致形成二溴丁烷。 三苯基膦-N-溴代琥珀酰亚胺介导的二醇的化学选择性环脱水用于合成多取代的四氢呋喃。1,4-二元醇及其衍生物可以快速环化,以高产率提供一当量的Ph 3 P / NBS。较高的Ph 3 P / NBS含量导致形成二溴丁烷。
Phase-transfer-catalyzed asymmetric Michael reaction using newly-prepared chiral quaternary ammonium salts derived from l-tartrate
作者:Shigeru Arai、Riichiro Tsuji、Atsushi Nishida
DOI:10.1016/s0040-4039(02)02415-2
日期:2002.12
The catalytic asymmetric Michael reaction of a glycine Schiff base was demonstrated using new PTCs and moderate to good ee's were achieved (up to 77% ee).