Journal of the Chemical Society. Perkin transactions I p. 3257 - 3266 (1992)
Update date:2022-08-05
Topics:
Fleming, Ian
Lewis, Jeremy J.
Methylation of the enolates 7, 24, 28 and 33 and protonation of the enolates 10, 27, 31 and 36 are diastereoselective in conformity to a general rule, summarised in the drawing 1, governing the stereochemistry of electrophilic attack on a double bond adjacent to a stereogenic centre.The sense of the selectivity is, with one exception, opposite to that of the corresponding nucleophilic attack on a carbonyl group adjacent to a stereogenic centre, which, with the same exception, follows Cram's and the Felkin-Anh rule, summarised in the drawing 2.The exception is probably the reduction 40 -> 38 + 39, with 39 as the major product.This result is inconsistent with Cram's and the Felkin-Anh rule if the isopropyl group is counted as 'larger' than the phenyl group, whereas the Grignard reaction 37 -> 38 + 39, where 39 is again the major product, and the corresponding electrophilic reactions 33 -> 34 + 35, with 34 as the major product, and 36 -> 34 + 35, with 35 as the major product, are all consistent with isopropyl being effectively larger than phenyl.
View MoreShanghai Potomer International Trade CO., LTD
Contact:+86-21-61397128
Address:Room 304,No.505 ,Caoyang Road.Shanghai,China
Changzhou Sunlight Pharmaceutical Co., Ltd.
Contact:+86-519-83131668;83139028;83138042;83137041
Address:JiuliStreet, Benniu Town Changzhou City, Jiangsu Province
Buffett (China) Holding Co.,Ltd
Contact:4006570891
Address:
BrightGene Bio-Medical Technology Co., Ltd.
website:https://en.bright-gene.com/
Contact:+86-512-62551801
Address:Building C25 - C31, No. 218 Xinghu Road, Suzhou Industrial Park, Suzhou, Jiangsu, China.
Weifang Dongxing Chitosan Factory
website:http://dxchitosan.lookchem.com/
Contact:13475651157
Address:Weifang city ,shandong province
Doi:10.1021/jo010633b
(2002)Doi:10.1023/A:1025593715104
(2003)Doi:10.1016/S0040-4039(00)81577-4
(1983)Doi:10.1016/S0040-4039(01)02391-7
(2002)Doi:10.1016/S0040-4039(01)02319-X
(2002)Doi:10.1139/v96-151
(1996)
