Pd(0) or Pd(II)-catalyzed ring-opening reactions of benzylidene- and alkylidenecyclopropyl ketones and aldehydes
摘要:
Pd(0) catalyzed reactions of methylenecyclopropyl carbonyl compounds afforded a convenient method for the synthesis of conjugate (E,E)-1,3-diene derivatives 2 in good to excellent yields. Moreover, we also found that Pd(II)-catalyzed reactions of methylenecyclopropyl carbonyl compounds with water gave 1,5-diketones in good to high yields via a carbene-palladium intermediate. The plausible reaction mechanisms have also been provided on the basis of control and O-18-labeling experiments. (c) 2009 Elsevier Ltd. All rights reserved.
HOTf-Catalyzed Rearrangement of Methylenecyclopropane Aryl and Alkyl Alcohols
作者:Xiang-Ying Tang、Min Shi
DOI:10.1002/ejoc.201000509
日期:2010.7
An efficient method to synthesize multisubstituted naphthalene and cyclobutanol derivatives through ring opening/ring enlargement of readily available methylenecyclopropane diaryl alcohols or dialkyl- and monoalkyl- as well as monoaryl alcohols in moderate to good yields has been described in this paper. The formation of naphthalene derivatives is a sequential reaction involving a cation-induced ring
Ring-Opening Reaction of Methylenecyclopropanes Derived from Methylenecyclopropyl Aldehydes through Cope Rearrangement
作者:Xiang-Ying Tang、Yin Wei、Min Shi
DOI:10.1002/ejoc.201000880
日期:2010.11
Tandem Wittig reaction/Cope rearrangement of methylenecyclopropyl aldehydes 1 with cinnamyltriphenylphosphonium bromide afforded a convenient method for the synthesis of cyclopentene derivatives 2 in moderate yields in a one-pot manner. Dialkyl 2-[(2-methylenecyclopropyl)methylene]malonates 3 derived from methylenecyclopropyl aldehydes 1 could produce two kinds of cyclopentene derivatives, 4 and 5
Organo-Selenium Induced Radical Ring-Opening Intramolecular Cyclization or Electrophilic Cyclization of 2- (Arylmethylene)cyclopropylaldehyde: A Tunable Synthesis of 1-Naphthaldehydes or 3-Oxabicyclo[3.1.0]hexan-2-ols
作者:Maozhong Miao、Xian Huang
DOI:10.1021/jo900805a
日期:2009.8.7
1-Naphthaldehydes and 3-oxabicyclo[3.1.0]hexan-2-ols can be prepared, respectively, by the intramolecular alkylation and cyclization of (E)-2-(arylmethylene)cyclopropylaldehyde 1 mediated by different organo-selenium reagents. The properties of selenium reagents may play an important role in the reactions. A rationale for these transformations is proposed.
Substrate-Controlled Selective Proximal and Distal C−C Bond Cleavage via Lewis Acid Mediated O-Acylation of 2-(Arylmethylene)cyclopropylaldehyde: A Stereoselective Synthesis of Bifunctional Methylenecyclobutanes and 1,3-Conjugated Dienes
作者:Xian Huang、Maozhong Miao
DOI:10.1021/jo801021f
日期:2008.9.1
ZnCl2-mediated reactions of (E)-2-(arylmethylene)cyclopropylaldehyde 1 with various acylchlorides provide a novel method for stereoselective synthesis of bifunctional methlylenecyclobutanes via a proximal-bond cleavage process. Nevertheless, when (Z)-1 was employed, the reactions give 1,3-conjugated dienes through distal-bond cleavage.
Thermally Induced Electrocyclic Reaction of Methylenecyclopropane Methylene Diketone Derivatives: A Facile Method for the Synthesis of Spiro[2.5]octa-3,5-dienes
作者:Xiang-Ying Tang、Yin Wei、Min Shi
DOI:10.1021/ol102002f
日期:2010.11.19
Thermally induced electrocyclic reactions of methylenecyclopropane (MCP) methylene diketone derivatives afford a novel method for the synthesis of spiro[2.5]octa-3,5-dienes in moderate to good yields. Applying this methodology in a one-pot manner for the reactions of MCP aldehydes with 1,3-diketones, catalyzed by l-proline, also afforded the corresponding spiro derivatives.