In the presence of a catalytic amount of NidppeCl(2), 2-methoxy-5,6-dihydro-2H-pyran reacts with primary Grignard reagents to give the corresponding 2-n.alkyl-5,6-dihydro-2H-pyrans in satisfactory yields. (C) 1998 Elsevier Science Ltd. All rights reserved.
DELAUNAY J.; LEBOUC A.; RIOBE O., BULL. SOC. CHIM. FRANCE, 1979, PART 2, NO 9-10, 547-551
作者:DELAUNAY J.、 LEBOUC A.、 RIOBE O.
DOI:——
日期:——
ZHOU, JINGYAO;LU, GUODI;HUANG, XIN;WU, SHIHUI, SYNTH. COMMUN., 21,(1991) N, C. 435-441
作者:ZHOU, JINGYAO、LU, GUODI、HUANG, XIN、WU, SHIHUI
DOI:——
日期:——
Catalytic Ring Expansion of Vinyl Oxetanes: Asymmetric Synthesis of Dihydropyrans Using Chiral Counterion Catalysis
作者:Boying Guo、Gregg Schwarzwalder、Jon T. Njardarson
DOI:10.1002/anie.201201367
日期:2012.6.4
Acid Showdown! The first catalyticring expansion of vinyl oxetanes to 3,6‐dihydro‐2H‐pyrans is described. Copper(II) triflate emerged as the best catalyst for this new transformation, which has broad scope as demonstrated by the eighteen examples included. The symmetric vinyl oxetane substrate can be asymmetrically desymmetrized when using either chiral Lewis or Brønsted acids as catalysts.