Regio- and stereoselective cyclopropanation of functionalised dienes. Novel methodology for the synthesis of vinyl- and divinyl-cyclopropanes
摘要:
Dienes, bearing an electron-withdrawing substituent at C-1, are cyclopropanated regio- and stereo selectively at the C-C double bond proximal to this electron-withdrawing group. The highest selectivity is observed in the case of dienylboronates. The cyclopropanation of these substrates affords almost exclusively the synthetically useful 1-boronato-2-vinyl-cyclopropanes. (C) 2002 Elsevier Science Ltd. All rights reserved.
<i>gem</i>-Selective Cross-Dimerization and Cross-Trimerization of Alkynes with Silylacetylenes Promoted by a Rhodium-Pyridine-<i>N</i>-Heterocyclic Carbene Catalyst
作者:Ramón Azpíroz、Laura Rubio-Pérez、Ricardo Castarlenas、Jesús J. Pérez-Torrente、Luis A. Oro
DOI:10.1002/cctc.201402327
日期:2014.9
The gem‐selective cross‐dimerization and ‐trimerization of silylacetylenes with alkynes through CH activation using a rhodium(I)–pyridine–N‐heterocyclic carbene catalyst have been developed. This reaction is applied to various aliphatic or aromatic terminal alkynes, internal alkynes, and gem‐1,3‐disubsituted enynes to afford the corresponding enynes and dienynes with high regio‐ and stereoselectivities
These Some other syntheses of homopropargylicalcohols havetypes of compounds are generally prepared by two main been also described: the classical homoaldol reaction ofpathways, the corresponding retrosynthetic analyses of chlorocrotylboronates with aldehydes furnishes homoallylicwhich are depicted on Scheme 1. alcohols bearing a chlorine atom on the double bond; thistype of molecule can undergo an
作者:John A. Soderquist、Karl Matos、Anil Rane、Jorge Ramos
DOI:10.1016/0040-4039(95)00322-4
日期:1995.4
The addition of B-methoxy-9-borabicyclo[3.3.1]nonane (1) to alkynyllithium reagents gives stable complexes (2) which undergo efficient Suzuki-Miyauracoupling to produce a variety of alkynyl derivatives (3).
The use of π-allyltricarbonyliron lactone complexes in the synthesis of the β-lactone esterase inhibitor (−)-valilactone.
作者:Roderick W. Bates、Rosalina Fernandez-Moro、Steven V. Ley
DOI:10.1016/s0040-4020(01)80728-6
日期:1991.12
A concise synthesis of the β-lactone esterase inhibitor valilactone (1) is reported. This synthesis employs the stereoselctive preparation of a π-allyltricarbonyliron lactone complex (7) that on oxidation with cericammoniumnitrate, affords an appropriately substituted β-lactone (9) which was transformed to (1).
A diastereoselective synthesis 1-trimethylsilyl-(E)-1,3-alkenynes and a simple synthesis of alkyl trimethylsilylethynyl ketones via organoboranes
作者:Narayan G. Bhat、Patricia Wawroski、Gonzalo Perez-Garcia、Mayra Elizondo
DOI:10.1016/j.tetlet.2005.05.134
日期:2005.8
A convenient, novel diastereoselective synthesis of 1-trimethylsilyl-(E)-1,3-alkenynes and a convenientsynthesis of alkyl trimethylsilylethynyl ketones based on Z-1-bromo-1-alkenylboronate esters are developed. α-Bromo-(Z)-1-alkenylboronate esters readily available using literature procedures smoothly undergo a reaction with trimethylsilylethynyllithium (derived from the deprotonation of trimethylsilylethyne