Asymmetric Direct Aldol Reaction Assisted by Water and a Proline‐Derived Tetrazole Catalyst

For example see:

10.1021/ja00031a069

10.1016/S0040-4039(00)73959-1

10.1016/S0040-4039(00)92656-X

10.1016/S0040-4039(97)00120-2

10.1016/S0040-4039(98)02238-2

10.1016/S0957-4166(00)80042-7

10.1016/0957-4166(95)00125-9

10.1039/p19840000291

10.1039/c39840001181

10.1021/jo01304a028

10.1021/jo961688u

10.1021/ol017120b

10.1139/v71-495

For recent reviews see:

10.1016/S0957-4166(97)00634-4

10.1002/(SICI)1521-3757(20000417)112:8<1406::AID-ANGE1406>3.0.CO;2-R

10.1002/(SICI)1521-3773(20000417)39:8<1352::AID-ANIE1352>3.0.CO;2-J

10.1016/S0040-4020(99)00964-3

10.1021/ar960027g

This work is based on the landmark contribution by List Lerner and Barbas III. See:

List B., 2000, J. Am. Chem. Soc., 122, 2396

10.1021/ja001460v

10.1021/ja010037z

10.1055/s-2001-18074

10.1016/S0040-4020(02)00516-1

10.1021/ol006976y

10.1021/jo015881m

Córdova A., 2002, Chem. Commun., 3204

For other asymmetric direct aldol reaction see:

10.1002/ange.19971091716

10.1002/anie.199718711

10.1021/ja990031y

10.1002/1615-4169(200201)344:1<1::AID-ADSC1>3.0.CO;2-A

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10.1246/bcsj.58.1401

Yamada Y., 1989, Utsunomiya Daigaku Kyoikugakubu Kiyo Dai‐2‐bu, 39, 25

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10.1055/s-1999-2786

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10.1016/S0040-4020(02)00965-1

The 83th (Spring) Annual Meeting of the Chemical Society of Japan 2003 Abstract II p. 1186.

In some respects our results compare well with the proline‐catalyzed reactions.[3]However what is different from proline is enhanced reactivity leading to a lower catalyst (5–10 mol %) and ketone (1–8 equiv) loading and even more expanded substrate scope regarding the ketone component. See also the Supporting Information for comparison experiments with proline.

After we finished this work the following important papers were published which also support our mechanism see:

10.1021/ol034461b

10.1021/jo026697j

One referee suggested that17might be formed from1and chloral deteriorating the catalytic activity of1. However we were unable to detect any1H NMR peaks corresponding to this during the aldol reaction but a very small doublet peak atδ=5.91 ppm (J=2.1 Hz) when1and chloral were mixed in a 1:1 ratio without2in CD3CN or MeOD at room temperature for one day.

The absolute configuration of4and5was determined by X‐ray single‐crystal analysis. See the Supporting Information.

10.1016/B978-0-12-507703-3.50007-5

10.1021/jp020079p

10.1021/ja011403h

10.1021/ja011714s

This enantioselective hydroxymethylation is now under investigation with other carbonyl compounds and the results will appear in a full account.