Readily available from esters or ketones, cyclopropanols are inclined to undergo diverse ring-opening transformations. Their one-electron oxidation is a conventional way to β-carbonyl radicals. However, despite this fact, their application as a coupling partner in dual photoredox and nickel-catalyzed reactions with organic halides remains underdeveloped. Here, we report that the Ti(OiPr)4 additive
环丙醇很容易从酯或酮中获得,倾向于进行各种开环转化。它们的单电子氧化是β-羰基自由基的常规方式。然而,尽管如此,它们作为偶联伙伴在与有机卤化物的双重光氧化还原和镍催化反应中的应用仍然不成熟。在这里,我们报告了 Ti(O i Pr) 4添加剂使这种难以捉摸的与芳基溴和烯基溴的交叉偶联成为可能,从而产生 β 取代的酮。
Three-Component Coupling of Acyl Fluorides, Silyl Enol Ethers, and Alkynes by P(III)/P(V) Catalysis
three-component coupling of acyl fluorides, silyl enol ethers, and alkynoates. The key to the success of the reaction is the formal transmetalation between pentacoordinate P(V) species (i.e., fluorophosphorane) and a silyl enol ether, which allows for C–C bond formation between the polarity-mismatched sites. The bond formation that cannot be attained even by transition metal catalysis is accomplished
New approaches toward the synthesis of (D-homo) steroid skeletons using Mukaiyama reactions
作者:Florence C.E. Sarabèr、Alexander Baranovsky、Ben J.M. Jansen、Maarten A. Posthumus、Aede de Groot
DOI:10.1016/j.tet.2005.11.056
日期:2006.2
Mukaiyama reaction between the silylenolether of 6-methoxytetralone and 2-methyl-2-cyclopentenone or carvone, with transfer of the silylgroup to the receiving enone, gave a second silylenolether. Addition of a carbocation, generated under Lewis acid conditions from 3-methoxy-2-butenol, 3-ethoxy-3-phenyl-2-propenol or 3-methoxy-2-propenol to this second silylenolether gave adducts, which could not
A new approach toward the synthesis of C,D-cis coupled steroid and C,D-cis coupled d-homosteroid skeletons
作者:Svetlana Dratch、Tanya Charnikhova、Florence C.E Sarabèr、Ben J.M Jansen、Aede de Groot
DOI:10.1016/s0040-4020(03)00629-x
日期:2003.6
procedure has been developed for the synthesis of C,D-cis coupled steroid and d-homo steroid skeletons. A Mukaiyama reaction with transfer of the silyl group of the starting silylenolether to the enol of the adduct followed by addition of vinyl magnesium bromide to the unprotected carbonyl group leads to adducts which can be cyclized with ZnBr2. The synthesis of functionalized steroid skeletons in overall
Tandem michael-michael-ring closure (mimirc) reactions
作者:Gary H. Posner、John P. Mallamo、Alison Y. Black
DOI:10.1016/s0040-4020(01)93265-x
日期:——
A new sequence of reactions involving tandem Michael-Michael-ring closure (MIMIRC) has been developed for efficient formation of three C-C bonds in one reaction vessel. The terminal ring closure reaction proceeds via either a 1,3- or a 1,6-cyclization, and this methodology also serves for construction of quaternary C centers. The usefulness of MIMIRC reactions is demonstrated by efficient assembly