1471-15-4Relevant articles and documents
Intramolecular Reaction of (γ-Alkoxyallyl)stannane with Aldehyde: Origin of the Stereoselectivities
Kadota, Isao,Kawada, Miho,Gevorgyan, Vladimir,Yamamoto, Yoshinori
, p. 7439 - 7446 (1997)
The intramolecular cyclization of simple acyclic (γ-alkoxyallyl)stannane aldehydes 1, 2, and 12-15 was investigated to elucidate the relationship between the geometry of the double bond of the allylstannanes, the ring size of cyclic ethers produced by the cyclization, and the procedures for promoting the cyclization. The Lewis acid-mediated cyclization of 1-2, 12-13, and 14-15 gave the trans cyclic ethers 3, 39, and 41, respectively, either predominantly or exclusively irrespective of the geometry of the double bond and of the ring size of the cyclic ethers. The relationship in the thermal cyclization of 1 and 2, which gave the 6-membered cyclic ethers 4 and 3, was straightforward; the Z isomer 1 gave the cis product 4, and the E isomer 2 afforded the trans product 3. However, the relationship in the thermal cyclization of 12 and 13 which afforded the 5-membered cyclic ethers 39 and 40 was different from that expected from the cyclization via the well-accepted cyclic transition state, as observed in the case of 1 and 2. Both the Z (12) and E (13) isomers gave the cis cyclic ether 40 either predominantly or exclusively. The protic acid-mediated (or -catalyzed) cyclization of 12-13 and 14-15 gave the trans cyclic ethers 39 and 41, respectively, regardless of the geometry of the double bonds. On the other hand, the protic acid-promoted cyclization of 1 and 2 was very strange; the Z isomer 1 gave the cis isomer 4, and the E isomer 2 afforded the trans isomer 3. The mechanisms for these cyclization reactions are proposed.
Intramolecular [4 + 3] cycloadditions - Stereochemical issues in the cycloaddition reactions of cyclopentenyl cations - A synthesis of (+)-dactylol
Harmata, Michael,Rashatasakhon, Paitoon,Barnes, Charles L.
, p. 1456 - 1469 (2006)
Five cyclopentanones were prepared for the purpose of examining the effects of stereogenic centers on the course of the intramolecular [4 + 3] cycloaddition reactions of cyclopentenyl cations. One substrate reacted with very high levels of diastereoselect
A convenient approach for the deprotection and scavenging of the PMB group using POCl3
Ilangovan, Andivelu,Saravanakumar, Shanmugasundar,Malayappasamy, Subramani,Manickam, Govindaswamy
, p. 14814 - 14828 (2013/09/02)
A convenient and high yielding approach for the deprotection and scavenging of the p-methoxybenzyl (PMB) group in PMB ethers and PMB esters was developed using POCl3 as the reagent. 4-Methoxybenzyl chloride, a starting material used for the preparation of PMB ethers and esters was regenerated in the deprotection step. This mild and selective procedure tolerates several acid sensitive functional groups. The Royal Society of Chemistry 2013.
Element having porphyrin polymer fixed on a substrate and method of preparing the same
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, (2008/06/13)
A photo-functional molecule element having, on a substrate, a porphyrin polymer containing covalently-fixed porphyrin units, and the method of preparing the same. The photo-functional molecule element may be used as a photoelectric conversion element such as an organic solar cell or a three-dimensional, non-linear organic material.