cis-2-Alkylcyclohexanols are obtained stereoselectively upon irradiation of a mixture of cyclohexene and the corresponding trialkylborane in the presence of p-xylene as a sensitizer and upon the successive oxidation of the photolysate with alkaline H2O2. The similar reaction of 1-ethylcyclohexene yields 2,2-dialkylcyclohexanols. Cycloheptene also reacts with the boranes to afford cis-2-alkylcycloheptanols
在对二甲苯作为敏化剂的存在下,对环己烯和相应的三烷基硼烷的混合物进行辐照,然后用碱性H 2 O 2连续氧化光解产物,可通过立体选择获得顺式-2-烷基环己醇。1-乙基环己烯的类似反应产生2,2-二烷基环己醇。环庚烯还与硼烷反应以提供顺式-2-烷基环庚醇。通过假定高度应变的反式-环己烯或-庚烯为反应性物质来解释这些反应。光化学产生的反式-环-辛-2-烯酮和顺式,反式-环-辛基-2,7-二烯酮与硼热反应,分别得到3-烷基环辛酮和顺式-7-烷基环辛-2-烯酮。cr啶与硼烷的光反应导致还原性烷基化,以相当好的收率得到9-烷基ac啶。
Iodine(V) Reagents in Organic Synthesis. Part 4. <i>o</i>-Iodoxybenzoic Acid as a Chemospecific Tool for Single Electron Transfer-Based Oxidation Processes
作者:K. C. Nicolaou、T. Montagnon、P. S. Baran、Y.-L. Zhong
DOI:10.1021/ja012127+
日期:2002.3.1
o-Iodoxybenzoic acid (IBX), a readily available hypervalent iodine(V) reagent, was found to be highly effective in carrying out oxidations adjacent to carbonyl functionalities (to form alpha,beta-unsaturated carbonyl compounds) and at benzylic and related carbon centers (to form conjugated aromatic carbonyl systems). Mechanistic investigations led to the conclusion that these new reactions are initiated
A New Method for the One-Step Synthesis of α,β-Unsaturated Carbonyl Systems from Saturated Alcohols and Carbonyl Compounds
作者:K. C. Nicolaou、Y.-L. Zhong、P. S. Baran
DOI:10.1021/ja001825b
日期:2000.8.1
oxidation cascades (entry 5, three oxidations in one pot). A range of small (Scheme 1, and entries 6-8 and 14-16, Table 1) and large (entries 9 -13, Table 1) ring ketones and alcohols are easily and controllably (Scheme 1 and entries 8, 10, and 13, Table 1) oxidized. Substitution at the Rand â-sites (R, entry 14;â, entries 15 and 18) of the carbonyl system does not hinder the reaction, nor does it diminish
Photoinduced Cycloaddition and Ene Reactions of 2,7-Cyclooctadienone: Experimental and Computational Studies of a Cyclopentyl Oxyallyl Intermediate
作者:Albert R. Matlin、Paul M. Lahti、Daniel Appella、Andrei Straumanis、Susanne Lin、Hiren Patel、Kyo Jin、Keith P. Schrieber、Jonathan Pauls、Patrick Raulerson
DOI:10.1021/ja984128g
日期:1999.3.1
cyclooctadienone 6 have been studied as a mode of entry to a cyclopentyl−oxyallyl system. Irradiation of cis,cis-2,7-cyclooctadienone 6 results in isomerization to cis,trans-2,7-cyclooctadienone 24. The strained dienone 24 is stable at −70 °C, but undergoes conrotatory cyclization at temperatures above −30 °C to the cis-bicyclo[3.3.0]oxyallyl system 25. The density functional theory (DFT) structural
Carbolithiation for the Generation of Cyclooctadienyl Anions and Tandem Electrocyclization/Alkylation to Functionalized <i>cis</i>-Bicyclo[3.3.0]octenes
作者:David R. Williams、Jonathan T. Reeves
DOI:10.1021/ja049353e
日期:2004.3.1
construction of functionalized cis-bicyclo[3.3.0]octenes has been developed. Carbolithiation of 3-methylene-1,4-cyclooctadiene with 1 degrees , 2 degrees , or 3 degrees alkyllithium reagents leads to cyclooctadienylanions, which undergo disrotatory electrocyclization and subsequent trapping with carbon, oxygen, sulfur, or silicon electrophiles to provide functionalized cis-bicyclo[3.3.0]octenes. Transmetalation