Premium
Stereoselective and Competitive [1,2]‐ and [2,3]‐Wittig Rearrangements of Allyl Heteroarylalkyl Ethers
Author(s) -
Capriati Vito,
Florio Saverio,
Ingrosso Giovanni,
Granito Catia,
Troisi Luigino
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(20022)2002:3<478::aid-ejoc478>3.0.co;2-#
Subject(s) - chemistry , stereoselectivity , wittig reaction , organic chemistry , stereochemistry , catalysis
Several allyl heteroarylalkyl ethers have been synthesized and then deprotonated with n BuLi in THF at −78°C to give lithium derivatives. The lithium‐bearing terminus was either the α‐ or the α′‐carbon atom, depending on the associated proton acidity. In the absence of an external electrophile, a sigmatropic rearrangement occurs, generating a new C−C bond. Heteroarylalkyl homoallylic alcohols and allyl heteroarylalkylic alcohols were obtained as products of stereoselective [2,3]‐ or [1,2]‐Wittig rearrangements, respectively. Homoallylic alcohols were obtained in high yields and with fairly good enantiomeric enrichments when the reactions were carried out in toluene with (−)‐sparteine as the external chiral ligand.